KR100297891B1 - Porous Absorption Macrostructure of Absorbent Particles Crosslinked with Cationic Amino-Epichlorohydrin Adducts - Google Patents

Abstract

Porous, absorbent macrostructures that, upon contacting liquids such as water or body exudates (e.g., urine), swell and imbibe such liquids, and are useful in absorbent articles such as diapers, adult incontinence pads, and sanitary napkins are disclosed. These porous macrostructures comprise bonded absorbent particles that are surface crosslinked with cationic, preferably polymeric, amino-epichlorohydrin adducts.

Description

Porous Absorbing Macrostructures of Absorbent Particles Cross-linked with Cationic Amino-Epichlorohydrin Adducts

Field of invention

The present invention relates to a porous absorbent macrostructure that swells and absorbs liquid upon contact with a liquid such as water or body excretion (eg, urine) and is useful in absorbent products such as diapers, adult incontinence pads, sanitary napkins and the like. The present patent application relates in particular to porous macrostructures of cationic, preferably polymeric, amino-epichlorohydrin adducts and surface crosslinked absorbent particles.

Background of the Invention

Granular absorbent polymer compositions can absorb large amounts of liquids, such as water and body excretion (eg, urine), and can further retain such absorbed liquids under moderate pressure. Due to the absorbent properties of these polymer compositions, the polymer compositions are particularly useful for incorporation into absorbent articles such as diapers. For example, US Pat. No. 3,699,103 to Harper et al., June 13, 1972 and US Pat. No. 3,770,731 to Harmon, dated June 20, 1972, were listed in absorbent products. The use of an absorbent polymer composition (also called a hydrogel, superabsorbent, or hydrocolloidal material) is described.

However, conventional particulate absorbent polymer compositions have limitations in that the particles are not fixed and move freely upon treatment and / or use. Due to the movement of the particles, not only are the materials lost in the manufacturing process, but the particles can also be heterogeneously incorporated into the structure in which the particles will be used. More serious problems arise when the particulate material moves during or after swelling during use. This mobility causes the liquid to have great resistance to passing through the material due to the lack of a stable capillary or liquid transfer channel between the particles. This phenomenon is commonly referred to as "gel blocking".

One way to address the performance limitations associated with particle mobility in use of absorbent articles is to incorporate the granular absorbent polymer composition into a tissue stack (layered absorbent structure). By encapsulating the particles between the tissue layers, the overall particle mobility in the absorbent structure is reduced. However, upon liquid contact, the particles in the stack often move freely with respect to each other, thus destroying the capillary channels between any particles already present.

Another way to solve this problem is to make the granular absorbent polymer composition non-flowable by adding a large amount of liquid polyhydroxy compound that acts as an adhesive to fix the particles to each other or to the substrate. An example of such a technique is described in US Pat. No. 4,410,571 to Korpman, dated October 18, 1983. This solution limits movement before and, to some extent, upon swelling, but the particles eventually separate from each other in the presence of excess liquid, destroying any preexisting capillary channels between the particles.

Another way to solve the mobility problem of these absorbent particles is to extrude a solution of linear absorbent polymer and subsequently crosslink the polymer to produce a superabsorbent film. Examples of this technique include US Pat. No. 4,861,539 (crosslinked with a polyhydroxy compound such as glycol or glycerol) to Allen et al. On August 29, 1989; ^(? Kymene), and issued to the 1978 second buck holder (Burkholder) to 28th day in the United States Patent 4,076,673 No. ^(? Kymene) a polyamine, such as-may add a polyamide epichlorohydrin described in being crosslinked with water) . Such superabsorbent films can absorb significant amounts of liquid, but are not substantially porous and therefore have limited liquid transfer properties due to the lack of internal capillary channels. Indeed, due to the lack of internal capillary channels, these superabsorbent films are particularly prone to blocking gels.

A recent method proposed to solve the problem of absorbent particle mobility is to form these particles into aggregate macrostructures, typically as sheets of bound absorbent particles. See US Pat. No. 5,102,597, issued April 7, 1992 to Roe. These aggregate macrostructures are prepared by first mixing the absorbent particles with a solution of a nonionic crosslinker, water and a hydrophilic organic solvent such as isopropanol. These nonionic crosslinkers include polyhydric alcohols (e.g. glycerol), polyaziridine compounds (e.g. 2,2-bishydroxymethyl butanol-tris [3- (1-aziridine) propionate]), haloepoxy compounds (E.g., epichlorohydrin), polyaldehyde compounds (e.g. glutaraldehyde), polyamine compounds (e.g. ethyleneamine), and polyisocyanate compounds (e.g. 2,4-toluene diisocyanate), preferably Is glycerol. See lines 22-54 of Roh et al., Patent Document 11 column.

Granular absorbent polymer compositions of the type used to make these aggregate macrostructures usually contain a number of carboxyl groups and are typically derived from polycarboxy compounds such as polyacrylates. When using glycerol as a crosslinking agent, the hydroxy groups of glycerol typically undergo esterification with the carboxy groups of the polymer present in the absorbent particles. Crosslinked ester bonds formed by glycerol occur not only on the surface of the absorbent particles, but also within the particles. This is because glycerol is a nonionic and relatively small molecule that can penetrate into absorbent particles. The resulting internal crosslinking lowers the absorbing capacity of the bound particles of the aggregate macrostructure.

In addition, the crosslinking reaction between the hydroxy group of glycerol and the carboxy group of the polymer present in the absorbent particles is relatively slow. Indeed, the absorbent particles treated with glycerol typically cure at 200 ° C. for 50 minutes. This provides a relatively weak sheet of bound absorbent particles, which ultimately becomes unwieldy in producing the desired absorbent structure. Therefore, it is necessary to treat these weak sheets with plasticizers such as mixtures of water and glycerol so that they are relatively flexible and easy to handle in producing absorbent structures.

Thus, (1) rapidly react with the carboxy groups of the polymer present in the absorbent particles at the surface of the absorbent particles to minimize the absorbent effect, and (2) provide improved absorbency and mechanical (tensile) properties for the aggregate macrostructures and (3) providing a flexible sheet of aggregate macrostructures that can be readily fabricated into absorbent structures used in diapers, adult incontinence pads, sanitary napkins, and the like; (4) crosslinkers that do not necessarily require organic solvents such as isopropanol It is desirable to be able to produce aggregate macrostructures of bound absorbent particles using.

Disclosure of the Invention

The present invention is directed to an improved porous absorbent macrostructure comprising intergranular aggregated aggregates. These aggregates comprise a plurality of absorbent precursor particles bound to each other at the aggregate surface, the particles comprising a substantially water-insoluble absorbent hydrogel-forming polymeric material having anionic functionality. These aggregates also comprise cationic, preferably polymeric amino-epichlorohydrin adducts in an amount sufficient to effect effective surface crosslinking, wherein the amino-epichlorohydrin adducts are absorbent at the surface of the precursor particles. Reacts with the polymeric material. These aggregates also have pores between adjacent precursor particles, which are connected to each other by interconnecting channels to form a liquid permeable macrostructure, so that the circumscribed dry volume of the macrostructure is at least about 0.008 kPa. do.

The invention also relates to a process for producing such porous absorbent macrostructures by providing a plurality of absorbent precursor particles and then treating them with a sufficient amount of cationic, preferably polymeric amino-epichlorohydrin adduct. . The treated precursor particles are physically bonded to form aggregates which react with the absorbent polymeric material of the precursor particles to produce effective surface crosslinks. The resulting porous absorbent macrostructures are useful in absorbent structures for various absorbent articles, including diapers, adult incontinence pads, sanitary napkins, etc., alone or in combination with other absorbent materials.

The porous absorbent macrostructures of the present invention and methods for their preparation provide many important advantages over previous porous absorbent macrostructures made of nonionic crosslinkers, in particular glycerol. The use of cationic, preferably polymeric amino-epichlorohydrin adducts as crosslinking agents according to the present invention reduces or eliminates crosslinking between particles to improve the rate of cure and improve the absorption of particles. This is because these adducts, especially relatively large cationic molecules, which are polymeric resins, cannot penetrate into the interior of the absorbent particles. It is also believed that at ambient temperatures between 18 and 25 ° C., cationic functional groups (eg, azetedinium) of these adducts react rapidly with the anionic, typically carboxy, functional groups of the polymeric material comprising absorbent particles. As a result, small amounts of crosslinking agents, such as 1% by weight of the absorbent particles, are required, while 4% by weight is typically required when using glycerol as the crosslinking agent.

The use of cationic, preferably polymeric amino-epichlorohydrin adducts provides other important advantages for porous absorbent macrostructures prepared using glycerol as crosslinker. Porous macrostructures of the present invention have improved absorbency and mechanical (tensile) properties. Unlike absorbent macrostructures crosslinked with glycerol, flexible absorbent macrostructures (such as sheets) according to the present invention require further treatment with a plasticizer afterwards (eg adding a mixture of water and glycerol). Can be prepared in a substantially one-step process. In addition, organic solvents such as isopropanol are not necessary to prepare the absorbent macrostructures according to the present invention.

1 is a micrograph of a cross-sectional view (34.9 times magnification) of a porous absorbent macrostructure in accordance with the present invention.

2 is an enlarged (75 times magnified) photograph of a part of the giant structure shown in FIG.

3 is an enlarged (200 times magnified) photograph of a part of the giant structure shown in FIG.

4 is an enlarged (400 times magnified) photograph of a part of the giant structure shown in FIG.

5 is a disposable diaper according to the invention wherein the absorbent member is part of a topsheet cut to more clearly show the lower absorbent core (an aspect of the absorbent member according to the invention) of the diaper comprising a porous absorbent macrostructure according to the invention. Perspective view of the sun.

6 is a cross-sectional view of the absorbent core of the diaper shown in FIG. 5 taken along cut line 6-6 in FIG.

7 is a perspective view of a disposable diaper aspect according to the present invention, with a portion of the topsheet cut away to more clearly show another dual-worm absorbent core aspect.

FIG. 8 is a blow-apart view of diaper components wherein the absorbent macrostructure is in the form of a number of strips and one of the components is a double caterpillar absorbent core of the other.

9 is a simplified perspective view of an apparatus for producing the absorbent macrostructure of the present invention in sheet form.

A. Porous Absorbing Macrostructures

Porous absorbent macrostructures according to the present invention are structures that can absorb large amounts of liquids, such as water and / or body excretion (eg, urine or menstrual blood) and can retain such liquids under moderate pressure. Due to the granular nature of the precursor particles, the macrostructure has pores between adjacent precursor particles. These pores are connected to each other by interconnection channels to make the macrostructures liquid permeable (ie have capillary movement channels).

Due to the bonds formed between the precursor particles, the resulting aggregate macrostructures have improved structural binding, increased liquid capture and distribution rates, and minimal gel-blocking properties. When the macrostructure is in contact with a liquid, the macrostructure is generally isotropically swollen, even at moderate confined pressures, absorbing the liquid into the pores between the precursor particles and then absorbing the liquid into the particles. Turned out. The circular swelling of the macrostructure allows precursor particles and pores to maintain their relative geometric and spatial relationships even when swollen. Thus, the macrostructures are relatively "fluid-stable" so that the precursor particles do not separate from each other, minimizing the frequency of gel blocking, and the capillary channels are retained and expanded upon swelling, so that the macrostructures retain liquid even if excess liquid is present. The liquid received can be moved.

The term " macrostructure " as used herein, when almost dried, is at least about 0.008 kPa, preferably at least about 10.0 kPa, more preferably at least about 100 kPa, most preferably about 500 kPa. It means a structure having the above circumferential volume (ie, circumferential dry volume). Typically, the macrostructures of the present invention will have a circumferential dry volume of at least about 500 mm 3. In a preferred aspect of the invention, the macrostructure has a circumferential dry volume of about 1000 kPa to about 100,000 kPa.

The macrostructures of the present invention may have a number of shapes and sizes and are typically present in the form of sheets, films, cylinders, blocks, spheres, fibers, filaments, or other shaped elements. The macrostructures generally have a thickness of about 0.2 mm to about 10.0 mm in diameter. For use in absorbent articles, the macrostructure is preferably in sheet form. As used herein, the term "sheet" refers to a macrostructure having a thickness of about 0.2 mm or more. The sheet will preferably have a thickness of about 0.5 mm to about 10 mm, typically about 1 mm to 3 mm.

As shown in FIGS. 1 to 4, the porous absorbent macrostructure of the present invention comprises aggregated particles. The interparticle bonded aggregates typically comprise at least eight independent precursor particles. In the preferred circumferential dry volume and size of the independent precursor particles used herein, these aggregated aggregates are typically formed from at least about 100,000 independent precursor particles. These independent precursor particles may include granules, fine powder, spheres, flakes, fibers, aggregates or aggregates.

As can be seen in FIG. 1 and FIG. 2, the independent precursor particles comprise a cube; Rod-shaped; Polyhedron; rectangle; Round type; Angular; Irregular shape; Irregular shapes of any size (e.g., grinding or grinding mills); or may have various shapes such as shapes having the largest dimension / smallest dimension ratio, such as acicular, flaky or fibrous shapes. have.

As shown in Figures 3 and 4, the intermolecular bonded aggregates comprising the macrostructures of the present invention are formed by essentially connecting or adhering with adjacent particles. The adhesive is substantially a polymeric material present on the surface of these particles. When these precursor particles are treated and physically bonded as described below, the polymeric material present on the surface of these particles is likely to have sufficient plasticity and cohesiveness (eg, to allow adjacent particles to adhere as discrete connections between the particles, typically). Stickiness). The crosslinking reaction between the amino-epichlorohydrin charge and the polymeric material of the particles fixes these adhesive structures such that the particles in the aggregate remain cohesive to each other.

B. Absorbent Precursor Particles

The macrostructures of the present invention are formed from polymeric materials that can absorb large amounts of liquid (such polymeric materials are commonly referred to as hydrogels, hydrocolloids or superabsorbent materials). The macrostructures preferably comprise absorbent hydrogel-forming polymeric material particles that are substantially water insoluble. Particular polymeric materials are described herein in the context of polymeric materials that form precursor particles.

Precursor particles can have a wide range of sizes, although certain particle size distributions and sizes are preferred. For the purposes of the present invention, particle size is defined in precursor particles that do not have the largest size / smallest size ratio, such as fibers (eg granules, flakes or powders) as the size of the precursor particles determined by sieve size analysis. do. Thus, for example, precursor particles residing on standard # 30 sieve with 600μ aperture can be thought of as having a particle size of 600μ or greater, passing through standard # 30 sieve with 600μ aperture and having standard # 30 with 500μ aperture Precursor particles staying on the 35th body can be thought of as having a particle size of 500 to 600μ, precursor particles passing through the # 35 sieve having a 500μ opening can be considered to have a particle size of less than 500μ. As a preferred embodiment of the present invention, the precursor particles generally have a size in the range of about 1 to about 2000 microns, more preferably about 20 microns to about 1000 microns.

Moreover, for the purposes of the present invention, the mass mean particle diameter of the precursor particles is important for determining the properties and properties of the resulting macrostructures. The mass average particle diameter of a given sample of precursor particles is defined as the particle size, which is the average particle diameter of the sample based on mass. The determination method of the mass average particle diameter of a sample is disclosed in the following test method piece. The mass average particle diameter of the precursor particles is generally about 20 to about 1500 microns, more preferably about 50 to about 1000 microns. In a preferred embodiment of the invention, the precursor particles have a mass average particle diameter of less than about 1000 microns, more preferably less than about 600 microns, most preferably less than about 500 microns. In certain preferred embodiments of the present invention, the mass mean particle diameter of the precursor particles is relatively small (ie, the precursor particles are fine). In this embodiment, the mass average particle diameter of the precursor particles is less than about 300 microns, more preferably less than about 180 microns. In an exemplary embodiment, at least about 95% by weight of the total particles have a particle diameter of about 150 to about 300 microns. In another aspect, at least about 95% by weight of the precursor particles have a particle diameter of about 90 to about 180 microns. A narrow distribution of precursor particle diameters is preferred because larger pore structures are created by having larger void portions when densified than when the particle size distribution of precursor particles having an equivalent mass mean particle size is wide. .

The particle diameter of a material with the largest / smallest size, such as a fiber, is typically defined by its largest size. For example, when absorbent polymer fibers (i.e., superabsorbent fibers) are used in the manufacture of the present invention, the length of the fibers is used to define the "particle diameter." (The denier and / or diameter of the fibers may also be specified. have). In an embodiment of the invention, the fibers have a length of at least about 5 mm, preferably from about 10 mm to about 100 mm, more preferably from about 10 mm to about 50 mm.

Precursor particles include substantially water-insoluble absorbent hydrogel-forming polymer materials having a number of anionic functional groups, such as sulfonic acids, more typically carboxy groups. Examples of suitable polymeric materials for use as precursor particles in the text include those made from polymerizable and unsaturated acid-containing monomers. Thus, such monomers include olefinically unsaturated acids and anhydrides containing at least one carbon to carbon olefinic double bond. More specifically, such monomers may be selected from olefinically unsaturated carboxylic acids and acid anhydrides, olefinically unsaturated sulfonic acids and mixtures thereof.

In addition, in order to manufacture this precursor particle | grain, some monomers other than an acid can also be used normally. Such non-acid monomers include, for example, water soluble or water dispersible esters of acid-containing monomers as well as monomers containing no carboxyl or sulfonic acid groups. Therefore, optional non-acidic monomers include monomers containing functional groups of the following types: carboxylic acid or sulfonic acid esters, hydroxyl groups, amide groups, amino groups, nitrile groups and quaternary ammonium salt groups, such Non-acidic monomers are well known materials, for example, US Pat. Nos. 4,076,663 and December 13, 1977, issued to Masuda et al., February 28, 1978, all of which are incorporated herein by reference. US Pat. No. 4,062,817 to Westman.

As the olefinically unsaturated carboxylic acid and carboxylic anhydride monomers, acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, α-cyanoacrylic acid, β-methylacrylic acid (crotonic acid) and α-phenyl are exemplified by acrylic acid itself. Acrylic acid, β-acryloxypropionic acid, sorbic acid, α-chlorosorbic acid, angelic acid, cinnamic acid, p-chlorocinnamic acid, β-steryl acrylic acid, itaconic acid, citraconic acid, mesaconic acid, glutamic acid, aco Nitric acid, maleic acid, fumaric acid, tricarboxyethylene and maleic anhydride.

Olefinically unsaturated sulfonic acid monomers include aliphatic or aromatic vinyl sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, vinyltoluene sulfonic acid and styrene sulfonic acid; Sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-acryloxy propyl sulfonic acid, 2-hydroxy-3-methacryloxy propyl sulfonic acid and 2 And acrylic and methacrylic sulfonic acids such as acrylamide-2-methylpropane sulfonic acid.

Preferred polymeric materials for use in the present invention have carboxyl groups. Such polymers include hydrolyzed starch-acrylonitrile graft copolymers, partially neutralized starch-acrylonitrile graft copolymers, starch-acrylic acid graft copolymers, partially neutralized starch-acrylic acid graft copolymers, Saponified vinyl acetate-acrylic ester copolymer, hydrolyzed acrylonitrile or acrylamide copolymer, slightly networked crosslinked product of the copolymers, partially neutralized polyacrylic acid, and slightly neutralized polyacrylic acid Network crosslinked products. These polymers can be used individually or in the form of mixtures of two or more monomers, compounds and the like. Examples of such polymeric materials are described in US Pat. Nos. 3,661,875, 4,076,663, 4,093,776, 4,666,983, and 4,734,478.

Most preferred polymeric materials for use as precursor particles are slightly networked crosslinked products of partially neutralized polyacrylic acid and starch derivatives therefrom. Most preferably, the precursor particles comprise about 50 to about 95%, preferably about 75%, neutralized, slightly networked crosslinked polyacrylic acid (ie, poly (sodium acrylate / acrylic acid)).

As described above, the precursor particles are preferably network crosslinked polymeric materials. Network crosslinking acts to make the precursor particles almost water insoluble, and in part to determine the absorption capacity and extractable polymer content properties of the precursor particles and the resulting macrostructures. Network crosslinking methods of polymers and typical network crosslinkers are described in more detail in US Pat. No. 4,076,663, cited above.

Individual precursor particles may be formed in a conventional manner. Typical and preferred methods for producing individual precursor particles include, but are not limited to, US Pat. No. 32,649 to Brantt et al. On April 19, 1988, incorporated herein by reference; U.S. Patent No. 4,666,983 to Tsubakimoto et al. On May 19, 1987; And U.S. Patent No. 4,625,001 to Tsubakimoto et al. On November 25, 1986.

Preferred methods for forming the precursor particles are those including aqueous solutions or other solution polymerization methods. As described in US Reissue Patent No. 32,649, cited above, aqueous solution polymerization involves the use of an aqueous reaction mixture to effect polymerization to form precursor particles. The aqueous reaction mixture is then subjected to sufficient polymerization conditions to produce a nearly network insoluble, slightly networked crosslinked polymeric material. The mass of polymeric material thereby formed is then crushed or chopped to form individual precursor particles.

More specifically, the aqueous solution polymerization method for producing the individual precursor particles includes a method for producing an aqueous reaction mixture for carrying out the polymerization to form the desired precursor particles. One element of this reaction mixture is an acid group-containing monomer material which forms the "backbone" of the resulting precursor particles. The reaction mixture generally comprises about 100 parts by weight of monomer material. Another component of the aqueous reaction mixture includes a networked crosslinker. Network crosslinkers useful for forming precursor particles include those described in US Reissue Patent Nos. 32,649; U.S. Patent No. 4,666,983; And US Pat. No. 4,625,001. Network crosslinkers are generally added to the aqueous reaction mixture in an amount of from about 0.001 to about 5 mole percent (about 0.01 to about 20 parts by weight based on 100 parts by weight of the monomer material) based on the total moles of monomers present in the aqueous mixture. exist. Optional components of the aqueous reaction mixture are, for example, sodium, potassium and ammonium persulfate, caprylyl peroxide, benzoyl peroxide, hydrogen peroxide, cumene hydroperoxide, tertiary butyl diperphthalate, tertiary butyl perbenzo Free radical initiators including peroxygen compounds such as ate, sodium peracetate, sodium percarbonate and the like. Other optional components of the water soluble reaction mixture include various non-acidic comonomer materials, including esters of essential unsaturated acidic functional group-containing monomers or other comonomers containing no carboxyl or sulfonic acid functional groups.

The aqueous reaction mixture is subjected to sufficient polymerization conditions to produce a mixture of nearly water-insoluble absorbent hydrogel-forming slightly networked crosslinked polymeric material. In addition, polymerization conditions are described in more detail in the patents cited above. Such polymerization conditions generally include heating (thermal activation techniques) to a polymerization temperature of about 0 to about 100 ° C, more preferably about 5 to about 40 ° C. Polymerization conditions for maintaining the aqueous reaction mixture also include, for example, exposure to the reaction mixture or, in part, its conventional forms of polymerization activating radiation. Other conventional polymerization techniques are radiation, electron, ultraviolet or electromagnetic irradiation methods.

In addition, the acid functionality of the polymeric material formed in the aqueous reaction mixture is preferably neutralized. Neutralization can be carried out in a conventional manner in which at least about 25 mole percent, more preferably at least about 50 mole percent, of the total monomers used to form the polymerizer material are acid group-containing monomers that are neutralized with salt forming cations. have. Such salt-forming cations include, for example, alkali metals, ammonium, substituted ammonium and amines, as discussed in more detail in the aforementioned US Reissue Patent No. 32,649 to Brant et al.

It is preferable to prepare the precursor particles using an aqueous solution polymerization process, but it is also possible to carry out the polymerization process using a multiphase polymerization method such as inversion emulsion polymerization or inversion suspension polymerization. In the inversion emulsion polymerization or inversion suspension polymerization process, as described above, the aqueous reaction mixture is suspended in the form of small droplets in a matrix of a water immiscible inert organic solvent such as cyclohexane. The precursor particles obtained are generally spherical in shape. The inversion suspension polymerization process is described in U.S. Patent No. 4,340,706 to Obaysashi et al. On July 20, 1982; United States Patent No. 4,506,052 to Flesher et al. On March 19, 1985; And US Patent No. 4,735,987, issued to Morita et al. On April 5, 1988, which are incorporated herein by reference.

In a preferred embodiment of the invention, the precursor particles used to form the interparticle crosslinked aggregates are substantially dried. “Substantially dry” in the text means that the precursor particles have a liquid content, typically water or other solution content, of less than about 50%, preferably less than about 20%, more preferably less than about 10% by weight of the precursor particles. Means that you have Generally, the liquid content of the precursor particles is in the range of about 0.01 to about 5 weight percent of the precursor particles. Individual precursor particles can be dried by conventional methods such as heating. Also, when forming precursor particles using an aqueous reaction mixture, water can be removed from the reaction mixture by azeotropic distillation. In addition, the polymer-containing aqueous reaction mixture may be treated with a dehydrating solvent such as methanol. Moreover, you may use together the said drying method. At this time, the dehydrated mass of the polymeric material may be chopped or pulverized to form substantially dry precursor particles of the absorbent hydrogel-forming polymeric material that are substantially water insoluble.

Preferred precursor particles of the invention are those which exhibit high absorption capacity such that the macrostructure formed from these precursor particles also has a high absorption capacity. Absorbent capacity refers to the capacity of the polymeric material to absorb the liquid when the polymeric material comes into contact with the liquid. The absorbent capacity varies greatly depending on the nature of the liquid being absorbed and the manner in which the liquid and the polymeric material are in contact. For the purposes of the present invention, absorbent capacity is defined as the amount of synthetic urine absorbed by a given polymeric material (defined later) in grams of synthetic urine per gram of polymeric material, according to the methods defined in the following test methods. Preferred precursor particles of the invention are those having an absorption capacity of at least about 20 g of synthetic urine per mole of polymeric material, more preferably at least about 25 g. Typically, the polymeric materials of the present precursor particles have an absorbent capacity of about 40 to about 70 g of synthetic urine per gram of polymeric material. Precursor particles having such relatively high absorbent capacity properties are particularly useful in absorbent articles, absorbent members, and absorbent products, since macrostructures made from these precursor particles by definition maintain body excretion, such as urine, in desired high amounts. .

Precursor particles of the cross-linked aggregate between the particles are preferably formed of the same polymer material having the same physical properties, while the present material need not be so. For example, some precursor particles may comprise a polymeric material of starch-acrylic acid graft copolymer, while other precursor particles may comprise a polymeric material of a slightly networked crosslinked product of partially neutralized polyacrylic acid. It may be. In addition, precursor particles of the interparticle crosslinked aggregates may vary in their absorbent capacity or other physical properties or properties by the shape of the precursor particles. In a preferred embodiment of the present invention, the precursor particles comprise polymeric materials consisting essentially of a slightly networked crosslinked product of partially neutralized polyaryl acid, each precursor particle having similar properties.

C. Cationic Amino-Epichlorohydrin Adduct

The main component of the interparticle bound aggregates comprising the porous macrostructures of the present invention is the addition of epichlorohydrin and certain types of monomeric or polymeric amines. These amino-epichlorohydrin adducts react with the polymeric materials of the absorbent precursor particles, especially the anionic functional groups, typically carboxy groups, of these polymeric materials to form bonds of the covalent ester type. In other words, the amino-epichlorohydrin adduct crosslinks the polymeric material present in the absorbent precursor particles (the polymeric material containing some of the absorbent precursor particles effectively crosslinked with the amino-epichlorohydrin adduct may be further crosslinked). Less swell in the presence of aqueous body fluid compared to the unbound particle portion).

These reacted amino-epichlorohydrin adducts are believed to provide crosslinking primarily at the surface of the absorbent precursor particles. This is because these adducts, especially their polymeric resin adducts, are relatively large cationic molecules. As a result, they cannot penetrate into the absorbent particles and can only react with the polymeric material on their surface. In addition, cationic functional groups (such as azetedinium groups) of these adducts, in particular their polymeric resins, can be rapidly reacted with the anionic functional groups, particularly carboxy groups, of the polymeric material of the absorbent particles even at room temperature (eg about 18 to about 25 ° C.). I think to respond. As a result, very suitable amounts of these amino-epichlorohydrin adducts (eg, about 1% by weight of the particles) are required to provide effective crosslinking to the surface of the polymeric material present in the absorbent precursor particles.

As used herein, "cationic amino-epichlorohydrin adduct" means a reaction product having two or more cationic functional groups formed by the reaction of epichlorohydrin with monomeric or polymeric amines. These adducts may be in the form of monomeric compounds (eg, reaction products of epichlorohydrin and ethylene diamine) or in polymeric form (eg reaction products of epichlorohydrin and polyamide-polyamines or polyethyleneimines). Can be. The polymeric compounds of these cationic amino-epichlorohydrin adducts are typically referred to as "resins".

One type of amino compound capable of reacting with epichlorohydrin to form adducts useful in the present invention is monomeric, dimeric, tertiary and higher amines having primary or secondary amino groups in these structures. Include. Examples of useful diamines of this type include bis-2-aminoethyl ether, N, N-dimethylethylenediamine, piperazine, and ethylenediamine. Examples of useful triamines of this type include N-aminoethyl piperazine, and dialkylenetriamines such as diethylenetriamine and dipropylenetriamine.

The amine material reacts with epichlorohydrin to form cationic amino-epichlorohydrin adducts useful herein as crosslinkers. For a more detailed description of these adducts as well as the preparation of these adducts, see US Pat. No. 4,310,593 and Ross et al., Issued January 12, 1982 to Gross . Organic Chemistry, Vol. 29, pp 824-826 (1964). All of these are incorporated herein by reference.

In addition to monomeric amines, polymeric amines such as polyethyleneimine can also be used as amino compounds. Particularly preferred amino compounds capable of reacting with epichlorohydrin to form the preferred cationic polymeric adduct resins useful herein are selected from certain polyalkylene polyamines and certain C ₃ -C ₁₀ divalent carboxylic acids. Polyamide-polyamine. Epichlorohydrin / polyamide-polyamine adducts of this kind are water soluble, thermoset, cationic polymers known in the art as wet strength resins for paper products.

In the preparation of polyamide-polyamines used to form preferred cationic polymeric resins of the above kind, the dicarboxylic acid is first reacted with the polyalkylene-polyamine in an aqueous solution, preferably water-soluble, and -NH (C _n H _2n HN) produces a long chain polyamide in which the _x- CORCO- groups, where n and X are each at least 2 and R is a C ₁ -C ₈ alkylene group of the dicarboxylic acid.

Various polyalkylene polyamines, including polyethylene polyamines, polypropylene polyamines, polybutylene polyamines, and the like can be used to prepare polyamide-polyamines, wherein polyethylene polyamines are an economically preferred kind. More specifically, the preferred polyalkylene polyamines used to prepare the cationic polymeric resins herein are polyamines comprising two primary amine groups and one or more secondary amine groups, wherein the nitrogen atoms are of the formula -C _n H _2n Linked together by groups, n is a small integer of at least 1 and the number of such groups in the molecule is from 2 to about 8, preferably up to about 4. Nitrogen atoms are attached to adjacent or farther carbon atoms of the —C _n H _2n — group, but not to the same carbon atom. It is also possible to use polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine and the like, which can be obtained in fairly pure form. Most preferred of the foregoing are polyethylene polyamines comprising 2 to 4 ethylene groups, 2 primary amine groups and 1 to 3 secondary amine groups.

It is also possible to use polyamine precursor materials comprising at least one tertiary amino group together with at least three amino groups. Suitable polyamines of this type include methyl bis (3-aminopropyl) amine, methyl bis (2-aminoethyl) amine, N- (2-aminoethyl) piperazine, 4,7-dimethyltriethylenetetramine, and the like. .

Dicarboxylic acids capable of reacting with the polyamines described above to form polyamide-polyamine precursors of the preferred cationic polymeric resins useful herein include saturated aliphatic C ₃ -C ₁₀ dicarboxylic acids. More preferred are those containing 3 to 8 carbon atoms, such as diglycolic acid, together with malonic acid, succinic acid, glutaric acid, adipic acid and the like. Of these, diglycolic acid and saturated aliphatic dicarboxylic acid having 4 to 6 carbon atoms in the molecule, that is, succinic acid, glutaric acid and adipic acid are most preferred. Not only can blends of two or more of the above dicarboxylic acids be used, but also with higher saturated aliphatic dicarboxylic acids such as azelaic acid and sebacic acid under conditions where the resulting long chain polyamide-polyamine is water soluble or at least water-dispersible. Blends of one or more dicarboxylic acids can be used.

The polyamide-polyamine material prepared from the above polyamines and dicarboxylic acids may be reacted with epichlorohydrin to form cationic polymeric amino-epichlorohydrin resins that are preferred for use as crosslinkers herein. Methods for the preparation of such materials are U.S. Patent No. 2,926,116, issued to Keim on February 23, 1960, which is incorporated herein by reference, and U.S. Patent No. 2,926,154, issued to Keim on February 23, 1960. And US Pat. No. 3,332,901, issued July 25, 1967 to Cambridge.

Polyamine-preferred cationic polyamide for use as crosslinking agents in the herein epichlorohydrin resin is marketed, e.g. Kymene ^(Kymenee?) In less particulates Herr, Inc.. Especially useful is the keymen ^? 557H, Kimen ^? 557LX and Keymen ^? As 557 plus, it is an epichlorohydrin adduct of polyamide-polyamine, which is the reaction product of diethylenetriamine and adipic acid. They are commercially available in the form of an aqueous solution of cationic resin material containing from about 10 to about 33% by weight active resin.

D. Preparation of Particle-Coupled Aggregates and Macrostructures

In preparing the intergranular aggregates constituting the porous absorbent macrostructure of the present invention, the absorbent precursor particles are treated with a sufficient amount of cationic amino-epichlorohydrin adduct to react with the polymeric material at the particle surface, thereby effectively Allow crosslinking to occur (ie, the crosslinked particle surface is less swollen in the presence of an aqueous body fluid than the uncrosslinked portion). Constructing an “adequate amount” of adduct depends on a number of factors including the particular absorbent precursor particle treated, the particular amino-epichlorohydrin adduct used, the particular effect desired to form an aggregated aggregate between particles, and the like. do. For monomeric amino-epichlorohydrin adducts, such as piperazine-epichlorohydrin adducts, the amount of adduct used is from about 0.1 to about 3 parts by weight, preferably from about 0.5 to about 1.5 parts by weight per 100 parts by weight of the absorbent precursor particles. Parts, most preferably about 0.8 to about 1.2 parts by weight. Kemen ^? For preferred polymeric amino-epichlorohydrin resins such as 557H, 557LX or Plus, the amount of resin used is from about 0.1 to about 5 parts by weight, preferably from about 0.5 to about 2.5 parts by weight, per 100 parts by weight of absorbent precursor particles. Preferably about 1 to about 2 parts by weight.

In addition to the absorbent precursor particles and the cationic amino-epichlorohydrin adduct, other components or other agents can be used as an adjuvant to prepare the aggregated aggregates between the particles. For example, water may typically be used with the adduct to form an aqueous treatment solution of the adduct. Water promotes uniform dispersion of the adducts on the surface of the precursor particles and allows the adducts to penetrate the surface area of these particles. Water also promotes stronger physical bonding between the treated precursor particles and provides the binding of the resulting cross-linked aggregates of aggregates. In the present invention, water is used in less than about 25 parts by weight (ie 0 to 25 parts by weight), preferably about 3 to about 15 parts by weight, more preferably about 5 to about 10 parts by weight per 100 parts by weight of precursor particles. . The actual amount of water used depends on factors such as the type of adduct used, the type of polymeric material used to form the precursor particles, the particle size of these precursor particles, the inclusion of other optional components (eg glycerol), and the like.

Although not absolutely necessary, organic solvents can be used to help uniformly disperse the cationic amino-epichlorohydrin adduct on the surface of the precursor particles. These organic solvents are typically hydrophilic and include lower alcohols such as methanol and ethanol: amides such as N, N-dimethylformamide and N, N-diethylformamide; And sulfoxides such as dimethyl sulfoxide. When using a hydrophilic solvent, the amount used is less than about 20 parts by weight (ie, 0 to about 20 parts by weight), preferably about 5 to about 15 parts by weight, more preferably about 8 to about 12 parts by weight, per 100 parts by weight of the precursor particles. Parts by weight. The actual amount of hydrophilic solvent used depends on factors such as the adducts used, the polymeric materials used to form the precursor particles, the particle diameter of these precursor particles, and the like.

As previously described, it is not necessary to use a hydrophilic organic solvent to prepare the combined particle aggregates of the present invention. In practice, it is desirable to avoid the use of such organic solvents. In general, the solvent needs to be removed from the aggregate to be suitable for its intended use. Removal of such organic solvents is often energy and process intensive and requires additional processing costs. Some hydrophilic solvents, such as isopropanol or t-butanol, cause amino-epichlorohydrin adducts to precipitate out of solution and are therefore not suitable for this reason. Indeed, the only solvents typically used to prepare the combined particle aggregates of the present invention are lower alcohols such as methanol and ethanol, which are not energy or process intensive and are not difficult to remove and the amino-epichlorohydrin adducts from the aqueous solution It does not allow to settle.

Other optional components can also be used with cationic amino-epichlorohydrin adducts, especially aqueous treatment solutions thereof. In particular, when the treated precursor particles are cured at ambient temperature as described below, it is particularly preferred that the treatment solution comprising the cationic amino-epichlorohydrin adduct comprises a plasticizer. In the absence of plasticizers, the treated precursor particles formed from the intergranular aggregates may be relatively fragile, making them more difficult to handle, particularly ultimately in the manufacture of the desired absorbent structure. The addition of a plasticizer to the resulting treatment solution forms a relatively flexible porous absorbent structure, in particular a flexible porous absorbent sheet, of the aggregated particles. These flexible sheets ultimately are relatively manageable in producing the desired absorbent structure.

Suitable plasticizers are water itself, or polymer solutions such as water and glycerol, propylene glycol (ie 1,2-propanediol), 1,3-propanediol, ethylene glycol, sorbitol, sucrose, polyvinyl alcohol, polyvinyl alcohol Combinations with other components such as ester precursors, polyethylene glycols or mixtures thereof. The other components in the plasticizer, such as glycerol, are considered to function as moisturizers, auxiliary plasticizers, or both together with water, which is the main plasticizer. Preferred plasticizers for use in the present invention are mixtures of glycerol and water, in particular when the weight ratio of glycerol to water is included as part of the aqueous treatment solution of the cationic amino-epichlorohydrin adduct. 1, preferably about 0.8: 1 to about 1.7: 1.

The actual amount of plasticizer used may vary depending on the particular plasticizer used, the type of polymeric material used to form the precursor particles, and the desired flexible effect from the plasticizer. Typically, the amount of plasticizer used is about 5 to about 100 parts by weight, preferably about 5 to about 60 parts by weight, more preferably about 10 to about 30 parts by weight, most preferably about 15 to about 100 parts by weight of precursor particles. About 20 parts by weight.

In the process of the invention, the absorbent precursor particles can be treated with cationic amino-epichlorohydrin adducts, typically aqueous solutions thereof, by any of a variety of techniques. This includes any method of applying a solution to a material, which method includes coating, dumping, pouring, or cationic amino-epichlorohydrin adduct, or a solution thereof on the absorbent precursor particles, And any technique used to apply the solution to the material, including dropping, spraying, atomizing, condensing, or dipping. "Apply to" in this text means that at least a portion of the surface area of the one or more precursor particles to be bound has an effective amount of adduct that causes to form surface crosslinks thereon. In other words, the cationic adduct is applied only on several precursor particles, on all precursor particles, on only part of the surface of some or all precursor particles, or on the entire surface of some or all precursor particles. Can be applied to the phase. Preferably, the adduct is coated on the entire surface of most precursor particles, preferably all precursor particles, in order to improve the efficiency, strength and density of interparticle crosslinking between the precursor particles.

In a preferred embodiment of the invention, after applying the treating solution onto the precursor particles, the treated precursor particles are mixed or laminated by any of a number of mixing or laminating techniques to ensure complete coverage with the treating solution. Since the precursor particles are completely covered with the treatment solution, the efficiency, strength and density of the bonds between the precursor particles as well as the crosslinks resulting from the reaction of the polymeric material with the cationic adduct forming the precursor particles are improved. Mixing can be performed using a variety of techniques and various apparatus, including various mixers or kneaders, as known in the art.

Before, during or after application of the treatment solution onto the precursor particles, the precursor particles physically bond together to form an aggregate macrostructure. By "physically bonded" in this context is meant that the precursor particles are in contact with each other as component parts in many different ways and in a spatial relationship to bond together to form a single unit (aggregate macrostructure).

The precursor particles are preferably physically defective together by applying a binder onto the precursor particles and physically contacting the precursor particles at the surface of at least some of the precursor particles to which the binder is applied. Due to the preferred binder, the polymer materials of the precursor particles upon bonding together adhere together by entanglement of the polymer chains due to the action of fluid surface tension and / or external swelling. Binders useful in the present invention include hydrophilic organic solvents, typically low molecular weight alcohols such as methanol or ethanol; water; Mixtures of hydrophilic organic solvents with water; The above cationic amino-epichlorohydrin adducts or mixtures thereof. Preferred binders are water, methanol, kymen ^? Cationic amino-epichlorohydrin adducts such as 557H, 557LX or plus, or mixtures thereof. Typically, the binder comprises a mixture comprising a cationic amino-epichlorohydrin adduct such that applying the adduct is performed concurrently with applying the binder.

The binders may be prepared by the various techniques and devices used to apply the solution to the material, including coating, dumping, pouring, spraying, angering, condensing or dipping them onto the precursor particles. It may be applied to these fields. The binder is applied on the surface area of at least some of the at least some precursor particles to be bonded together.

The binder is preferably coated on the entire surface of most precursor particles, preferably all precursor particles. The binder is generally mixed with the precursor particles by a number of mixing / spraying techniques and mixing / spraying apparatus to ensure that the precursor particles are completely covered with the binder.

When applying the binder to the precursor particles, the precursor particles can be physically contacted together in many different ways. For example, the binder alone can maintain contact between the particles. Alternatively, gravity can be used to ensure contact between precursor particles (eg, stacking precursor particles). Moreover, the particles can be placed in a container having a fixed volume to ensure contact between the precursor particles.

Precursor particles can also be physically bonded together by physically constraining them so that they contact each other. For example, precursor particles may be densely packed into a container having a fixed volume such that they are in physical contact with each other. In combination with the above methods or in other ways, gravity may be used to physically bind the precursor particles. In addition, the precursor particles may be physically bonded together through electrostatic attraction or by the use of an adhesive (eg, an adhesive material such as a water soluble adhesive) to bond them together. In addition, the precursor particles can be attached to the third member (substrate) and brought into contact with each other by the substrate.

In an optional method of forming the macrostructure of the present invention, the aggregates of precursor particles are molded into various geometries, spatial relationships and densities to form aggregates having defined shapes, sizes and / or densities. The aggregate may be molded by any conventional molding technique known in the art. Preferred molding methods for the aggregates include casting, formulation or forming operations. Casting and formulation techniques generally include introducing precursor particles into the prepared mold interior space and applying pressure to the assembly (compressing) to make the assembly suitable for the shape of the mold interior space. Examples of specific formulation techniques for use herein include compression formulations, injection formulations, extrusion or lamination. For example, the plurality of precursor particles may be in a container having a fixed volume of the mold interior space, and the aggregate may be compressed so that the resulting macrostructure has a shape defined by the shape of the mold interior space to suit the shape of the mold interior space. do. Forming techniques include performing various manipulations on an aggregate to modify its shape, and / or size, and / or density. Examples of specific forming techniques for use herein include rolling, forging, extrusion, spinning, coating or drawing operations. For example, an aggregate mixture of precursor particles and at least a cationic amino-epichlorohydrin adduct crosslinker may pass between a pair of compression rolls to form a sheet aggregate. Alternatively, the aggregate mixture may be extruded through an orifice to form an aggregate having a shape corresponding to the shape of the orifice. The aggregate mixture may also be cast on the surface to form an aggregate having the desired shape or surface morphology. Any or all of these techniques may also be used in combination to form shaped aggregates. Any suitable device known in the art may be used to perform this operation, which operation may be performed with a hot and / or cold material or part of the device.

In a preferred embodiment of the invention, a mixture mixture of precursor particles, cationic amino-epichlorohydrin adducts, water, a moisturizer / adjuvant plasticizer (optional) and a hydrophilic organic solvent is added to the hopper of a conventional extruder. . An example of an extruder device is shown in FIGS. 12-14 of pages 331 of Principles of Polymer Materials, Second Edition (McGraw-Hill Book Company, 1982), incorporated herein by reference. Is extruded through an orifice, and fed to a pair of driven extrusion rolls having a fixed (but variable) spacing between the rolls so that the extruder is compressed into a sheet form. The sheet is then processed to a specific length to provide a macrostructure with a specially manufactured size, shape and / or density.

In forming the aggregate macrostructures of the present invention into particular shapes, in particular sheets, the density must be carefully controlled. If the density of the molded aggregate macrostructure is too high, there is a tendency to gel blocking. In contrast, if the density is too low, the formed aggregate structure may have insufficient tensile strength and bondability. The molded aggregate macrostructures of the invention typically have a density of about 0.7 to 1.3 g / cc, preferably about 0.8 to about 1.1 g / cc, most preferably about 0.9 to about 1.0 g / cc.

Preferred methods and apparatus for continuous molding the aggregate macrostructures of the present invention into sheets are described in US Patent Application (Michael S. Kolodesh et al., "Method and Appartus for Making Cohesive Sheets from Particulate Absorbent", herein incorporated by reference. Polymeric Composition ", Inc. No. 4732). The continuous method of making the aggregate sheet will be best understood with reference to FIG. 9, which shows an apparatus 301 for doing this. Device 301 has a frame 302 that supports its various elements. The device 301 has support means as shown in FIG. As the conveyor 303 moving in the direction of the arrow 310 moves, the conveyor 303 first passes under the initial nebulizer 304a. After passing the initial nebulizer 304a, the conveyor 303 passes under one or more means of continuously depositing a predetermined amount of precursor particles on the conveyor. The feeder is shown as 305a-305e in FIG. Conveyor 303 also passes under one or more means for spraying a predetermined amount of treatment solution onto a layer of precursor particles on the conveyor. This is shown as atomizers 304b-304f in FIG. 9. Apparatus 301 also includes a pair of non-planar opposing pressurizers downstream of feeder 305 and nebulizer 304. The pressurizer is represented by a pair of compression rolls 306 in FIG. Also shown in FIG. 9 as part of the apparatus 301 are the slitting and moving conveyor 307, the knife and anvil roll 308, and the sheet accumulator 309.

Conveyor 303 may be a flat belt conveyor, such as polyurethane having good release properties commonly used in the food industry. The width of the conveyor is determined by the desired sheet size. The conveyor generally moves in the direction of arrow 310 from the point 311 where the initial sprayer 304a is located to the point 312 where the knife and anvil roll 308 is located. Conveyor 303 is a generally endless conveyor, as shown in FIG.

The conveyor 303 first passes under an initial nebulizer 304a, where the conveyor is sprayed with a predetermined amount of treatment solution to cover a predetermined area of the conveyor with the treatment solution. This initial spraying exposes the bottom of the first precursor particle layer to the treatment solution. In addition, the wet conveyor surface prevents the particles that are subsequently supplied from popping out at their desired locations. However, the initial spraying step is not absolutely necessary, especially if the first layer of particles is placed relatively thin on the conveyor or the conveyor moves at a slow speed.

The nebulizer 304a (both nebulizers 304b through 304f) should be sprayed with a substantially uniform mist, angered spray, and have a low impact force to prevent the precursor particles from flying away. One high performance nebulizer is the Model 6218-1 / 4 JAU furious air activated nozzle assembly, available from Spraying System Co., 60188, Illinois, USA.

The conveyor 303 then passes under a feeder 305a that deposits a predetermined amount of dry precursor particles onto the conveyor in a given area. The amount of precursor particles deposited onto the conveyor 303 depends on various factors including, but not limited to, the desired density of the resulting sheet, the number of lamination steps to be performed, the size of the particles used, and the desired width of the resulting sheet. The minimum amount of precursor particles should be substantially sufficient to cover a given area of the conveyor with one layer of thickness of one particle.

The feeder 305a (both the feeders 305b to 305e) should be able to distribute the precursor particles in a thin and wide layer. Thin layers on the conveyor allow all particles to be processed during subsequent spraying steps, and wider layers will increase productivity. It has been found that vibration feeders are preferred for laminating dry precursor particles on a conveyor. Suitable vibrating feeders are North Carolina, USA 28241-0767 South Lake Lake Drive 14201-A. Superfeed model # 2106E-003S4, available from Solids Flow Control, Inc., at 410767. This feeder has a weight feed-back control system for accuracy.

The conveyor 303 then passes under the second nebulizer 304b. Conveyor 303 in a given area having a first layer of precursor particles is sprayed with a predetermined amount of the same treatment solution as used in the initial spray gun 304a. Generally, a predetermined amount of treatment solution is related to the amount of particles in the layer. The greater the amount of particles in the layer, the greater the amount of treatment solution required to treat substantially all of the particles.

The metering and spraying steps (eg, using feeders 305b through 305e and nebulizers 304c through 304f) may then be repeated several times depending on the desired density of the ultimate sheet. As described above, when the metering and spraying steps are repeated several times and the initial spraying step is performed, the first layer of particles is exposed to two sprays. Therefore, the initial spraying step and the first post-lamination spraying step need to spray only half of the amount of treatment solution required to treat the amount of particles in the first layer on the conveyor 303, respectively. Other atomizers 304c-304f will spray a normal amount of treatment solution, ie, twice the amount of treatment solution after the initial or first lamination.

After all lamination and spraying steps have been performed, the treated precursor particles are typically loosely attached to one another to form a web. Conveyor 303 then moves and delivers this web to a pair of opposing presses. The pressurizer shown in FIG. 9 has the form of the granular roll 306. However, as will be appreciated by those skilled in the art, it is possible to use a discontinuous conveyor method with opposing plates or platens used to compress the web.

Compression roll 306 may have a non-planar rough surface. As the web passes through the compression roll 306 the pressure on the web causes the web to stretch. The rough surface of the roll 306 reduces the sliding effect between the roll and the web when the web is in contact with the roll. This in other words reduces the elongation of the web in both the machine direction 310 and the cross-machine direction. Machine direction stretching is undesirable because the speed must be increased for the compression roll 306 to match the machine direction stretching. Compression by the roll 306 densifies the treatment solution sprayed onto the web and sheet of the freely attached layer of precursor particles.

Compression roll 306 is in the form of a cylindrical stainless steel roll coated by plasma coating, which makes the roll surface rough and makes the web more easily released after compression. Examples of suitable coatings are Coatings # 934 and # 936, commercially available from Plasma Coating Inc., Connecticut, United States. The gap between the compression rolls determines the degree of compression applied to the web.

The device 301 may include slitters for cutting and trimming the web edges prior to compression. The edges of the web may have a less uniform density than other parts of the web, and are typically removed because the treatment solution and particles are applied discontinuously due to the movement of the conveyor belt in the transverse machine direction. The slitter may be a conventional circular knife that acts on a hard surface, such as a moving conveyor belt (indicated by 307).

After the web passes through the compression roll 306, the sheet is formed and collected in the accumulator 309. The accumulator 309 may take the form of a winding roll that winds the sheet into a single roll of a desired size. When obtaining a roll of the desired size, the device 301 may have a second slit for cutting the sheet. This second slitter may take the form of a knife and anvil roll 308.

Simultaneously with or after adapting the cationic amino-epichlorohydrin adduct, the precursor particles are physically bonded to each other to form an aggregate, which aggregate is shaped and the precursor particles in the aggregate while maintaining the physical bond of the precursor particles. Reacts with the polymeric material of to form surface crosslinks between precursor particles of the aggregate macrostructure. Because of the relatively reactive cationic functionality of the cationic amino-epichlorohydrin adduct used in the present invention, the crosslinking reaction between the adduct and the polymeric material of the precursor particles can be carried out at relatively low temperatures. Indeed, such crosslinking reactions (curing) can be carried out at ambient room temperature. Such ambient curing is particularly preferred when the treatment solution comprising the adduct optionally contains a plasticizer, such as a mixture of water and glycerol. Curing at temperatures significantly above ambient temperature removes the plasticizer due to its volatility and requires an additional step to plasticize the resulting intermolecular bound aggregates. The ambient curing is typically performed at about 18 to about 35 ° C. for about 12 hours to about 48 hours. Preferably, the ambient temperature curing is performed at about 18 to about 25 ° C. for about 24 hours to about 48 hours.

The crosslinking reaction between the cationic amino-epichlorohydrin adduct and the polymeric material of the precursor particles may be carried out at ambient temperature, but such curing may also be carried out at higher temperatures to speed up the reaction. High temperature curing typically heats the treated and bonded precursor particles such that crosslinking between the adduct and the polymeric material of the precursor particles occurs in a shorter time, typically a few minutes. This heating step can be carried out using many conventional heating devices, including various ovens or dryers known in the art.

Generally, heat curing is carried out by heating to a temperature of about 50 ° C. or more for a time sufficient to complete the crosslinking reaction between the adduct and the polymeric material of the precursor particles. The specific temperature and time used during heat curing depends on the particular cationic amino-epichlorohydrin adduct used and the polymeric material present in the precursor particles. If the temperature is too low or the time is too short, the reaction will not occur sufficiently, resulting in the formation of macrostructures with insufficient binding and poor absorption. If the temperature is too high, the absorption of the precursor particles may be reduced, or depending on the particular polymeric material, may drop to the point where the macrostructure resulting from the network crosslinking of the precursor particles is not useful for absorbing large amounts of liquid. have. In addition, if curing time and temperature are not appropriate, the extractable amount of the resulting aggregates may be increased, thereby increasing the occurrence of certain types of gel blocking. Therefore, the reaction is generally carried out for about 1 to about 20 minutes at a temperature of about 50 to about 205 ℃. Preferably at about 180 to about 200 ° C for about 5 to about 15 minutes. The actual time and temperature used will vary depending on factors such as the particular polymeric material used for the precursor material, the particular adduct used, the thickness or diameter of the associated macrostructure, and the like.

The crosslinking reaction between the cationic amino-epichlorohydrin adduct and the polymeric material of the precursor particles occurs sufficiently fast at ambient temperature to be able to carry out this reaction in the absence of initiator and / or catalyst. However, an important factor in proportion to the reactivity of the cationic amino-epichlorohydrin adduct is the pH of the treatment solution containing the adduct. Typically, the pH of the treatment solution is about 4 to about 9, preferably about 4 to about 6. Maintaining pH in this range of the treatment solution ensures that the cationic amino-epichlorohydrin adduct is sufficiently reactive at ambient temperature.

In order for the adjacent precursor particles to aggregate cohesively with each other during crosslinking, the physical bonding of the treated precursor particles needs to be maintained during the curing step. If the forces or stresses present during the crosslinking are sufficient to decompose the precursor particles, insufficient bonding of the precursor particles may occur. This allows the aggregate to have poor structural binding. Physical bonding of the precursor particles is typically maintained by allowing minimal decomposition or stress to be introduced during the curing step.

As described above, the steps of the method of the present invention for producing macrostructures do not need to be performed in any particular order. For example, the cationic amino-epichlorohydrin adduct is applied simultaneously with the physical bonding of the precursor particles, molded into the desired shape and typically the desired density, after performing the steps or after the assembly has been left for a period of time. The precursor particles may then be simultaneously reacted with the polymeric material of the precursor particles to surface crosslink and form aggregate macrostructures. Typically, the precursor particles are mixed with or sprayed with a solution of adducts, water, humectants and / or coplasticizers (e.g. glycerol), and hydrophilic organic solvents (e.g. methanol) to form aggregates adhered to each other. do. Adducts, water, humectants / adjuvant plasticizers and hydrophilic organic solvents act as binders for precursor particles, and adducts also act as crosslinkers. The bonded aggregates (ie, bound precursor particles and aqueous mixture) are subsequently molded into dense sheets by a combination of extrusion and rolling techniques as described above. The adduct is then reacted or thermally cured with the polymeric material at ambient temperature to crosslink at the precursor particle surface and form a cohesive aggregated aggregate macrostructure.

Under certain conditions, especially when the treated precursor particles are thermoset, the resulting macrostructures can crumble well without being somewhat soft. In such a case, it is possible to make the macrostructure more flexible by adding a plasticizer. Suitable plasticizers are water alone or preferably comprise a mixture of water with a moisturizer / adjuvant plasticizer, such as glycerol, as described above. Plasticizers can be applied to the macrostructures in a number of different ways, including spraying, coating, angering, dipping or dumping the solution into the macrostructures. Alternatively, when only water is used, the macrostructure can be placed in a high humidity environment (eg, relative humidity above 70%). The amount of plasticizer applied to the macrostructure can be selected depending on the specific plasticizer used and the desired effect. Typically, the amount of plasticizer applied is about 5 to about 100 parts by weight, preferably about 5 to about 60 parts by weight per 100 parts by weight of the macrostructure. Particularly preferred plasticizers comprise a mixture of glycerol and water in a weight ratio of about 0.5: 1 to about 2: 1, preferably about 0.8: 1 to about 1.7: 1.

As shown in FIGS. 1 to 4, the macrostructures produced according to the present invention have pores (dark areas of the micrograph) between adjacent precursor particles. Pores are small gaps between adjacent precursor particles that allow liquid to pass into the interior of the macrostructure. The pores are formed into macrostructures because the precursor particles are not tightly “fit” or packed in such a way that the pores will disappear even if they are compressed (the filling efficiency of the precursor particles is less than one). The pores are generally smaller than the constituent precursor particles and provide a capillary between the precursor particles, moving the liquid into the macrostructure.

The pores are connected to each other by the effector connecting channels of the technicians. The channel is used to absorb this liquid because the liquid contacts the macrostructure and moves through capillary forces (ie, through the formed capillary channels) to other parts of the macrostructure. In addition, upon expansion, the pores and interconnected channels allow the liquid to pass through the macrostructure into a lump of precursor particles away from the initiation of liquid contact or into another structure in contact with the macrostructure. Thus, macrostructures are thought to be permeable to liquids due to the pores and the interconnected channels.

Porosity (ie, the total volume of the macrostructure comprising pores and channels) has a minimum value for the distribution of specific precursor particle sizes. In general, the narrower the distribution of precursor particle sizes, the higher the porosity will be. Thus, it is desirable for the precursor particles to have a fertilizer narrow particle size distribution to provide a higher porosity in the compressed state.

Another feature of the macrostructures of the present invention is that when the liquid is deposited on or in contact with the macrostructure, the macrostructure generally isotropically swells, even under moderate oil pressure. Isotropic swelling is used herein to mean that when the macrostructures are wet, they generally swell equally in all directions. Isotropic swelling is an important property of macrostructures because precursor particles and pores retain their relative geometric shapes and spatial relationships even when they are swollen so that existing capillary channels are retained in use if they are not enlarged. Larger when swollen). The macrostructures can thus absorb the liquid and / or transport additional liquid filled by itself without gel blocking.

The formation of crosslinks in the macrostructures between the independent precursor particles indicates that the resulting macrostructures are stable to fluids (ie liquids). "Fluid stability" as used herein means that macrostructures comprising cross-linked aggregates between particles remain almost intact upon contact with or in swelling in an aqueous fluid (ie, most of the independent component precursors). Particles remain bound together). Although fluid stability is defined as most precursor particles bound together, it is preferred that all precursor particles used to construct the macrostructures be bound together. However, it should be appreciated that some precursor particles may decompose themselves from the macrostructure if other particles are agglomerated into the macrostructure by water.

Fluid stability is an important feature of the macrostructures of the invention because it is encased to maintain its structure in dry and wet (swelled) conditions and holds the precursor particle components. In end products, such as absorbent members or absorbent articles, the precursor particles are confined even when in contact with the liquid, so that fluid stability reduces gel blocking and uses the independent particulates in a coarse form, thereby reducing the element of gel blocking. It is advantageous to increase the fluid absorption rate of the resulting macrostructures without introduction.

The fluid stability of the aggregate macrostructure can be determined by a two step process. The initial dynamic reaction of the aggregate macrostructures upon contact with the aqueous emulsion is observed, followed by the aggregate macrostructures in equilibrium conditions with sufficient swelling. Test methods for determining fluid stability by these criteria are described in the Test Methods section below.

In use, liquid deposited on or in contact with the macrostructures is either absorbed by the precursor particles, or passed through the pores, to be moved to other sites of the macrostructures, where they are absorbed by the other precursor particles or the macrostructures are removed. Through to the other absorbent member adjacent thereto.

Various types of fiber materials can be used for the reinforcing members in the macrostructures of the present invention. Any type of fibrous material suitable for use in conventional absorbent articles is also suitable for use in the present macrostructures. Specific examples of such fibrous materials include cellulose fibers, modified cellulose fibers, rayon, polypropylene, and polyester fibers such as polyethylene terephthalate (DACRON) and hydrophilic nylon (HYDROFIL). In addition to the materials described above, examples of other fiber materials used in the present invention include surfactants derived from hydrophilized hydrophobic fibers such as polyolefins such as polyethylene or polypropylene, polyacryl, polyamides, polystyrenes and polyurethanes, and the like. -Treated or silica-treated thermoplastic fibers. In fact, hydrophilized hydrophobic fibers do not provide a web of sufficient absorbing capacity to be useful for conventional absorbent structures because they are not so absorbent, but because of their good suction properties they are suitable for use in the macrostructures of the present invention. This is because, in this macrostructure, the propensity to inhale the fibers is less important than the absorption capacity of the fiber material itself, but is important because of the high fluid absorption rate and lack of gel blocking properties of the macrostructures of the present invention. Synthetic fibers are generally preferred for use herein as the fiber component of macrostructures. Most preferred are polyolefin fibers, preferably polyester fibers.

Other cellulose fiber materials that may be useful for any macrostructure in the text are chemically strengthened cellulose fibers. Chemically strengthened preferred cellulose fibers are reinforced, twisted, curled cellulose fibers that can be prepared by internally crosslinking the crosslinker and the cellulose fibers. Types of reinforced, twisted, curled cellulose fibers useful as the present hydrophilic fibrous material are described in US Pat. No. 4,888,093 to Dean et al., Dated Dec. 19, 1989; United States Patent No. 4,889,595 to Herron et al. On December 26, 1989: United States Patent No. 4,889,596 to Schoggen et al. On December 26, 1989; US Patent No. 4,889,597 to Bourbon et al. On December 26, 1989 and US Patent No. 4,898,647 to Moore et al. On February 6, 1990. These patent documents are each incorporated by reference in the text.

In the text, "hydrophilic" means that the fibers or surfaces of fibers are deposited on the fibers (if the fibers actually absorb emulsions or form gels, if water or body excretion readily disperses on the surfaces of the fibers). It is wetted by liquid. The technical literature on the wetting of materials defines the hydrophobicity (and wettability) by contact angle, and the surface tension of the liquids and solids involved. This is described in detail in the American Chemical Society Publication entitled "Contact Angle, Wettability, and Adhesion", edited by Robert F. Gould and copyrighted in 1964. When the contact angle between the liquid and the fiber or surface is less than 90 °, or when the liquid tends to spontaneously disperse over the surface of the fiber, or when these two conditions are universally present at the same time, the surface of the fiber or fiber It can be said that it is wet by the liquid.

The fiber material may be added to the macrostructure by introducing the fiber with the interparticle crosslinker into the solution and mixing with the precursor particles before applying the interparticle crosslinker or by adding the fiber material to the interparticle crosslinker / precursor particle mixture. It may be. For example, the fiber material is kneaded into an interparticle crosslinker / precursor particle mixture. The fibrous materials are preferably mixed well with the solution so that they are uniformly dispersed in the macrostructure. The fibers are also preferably added before reacting the adduct with the polymeric material of the precursor particles.

The relative amount of fibrous material mixed with the precursor particles can vary widely. The fiber material is preferably added at about 0.01 to about 50 parts by weight, more preferably about 0,5 to about 5 parts by weight per 100 parts by weight of the precursor particles.

E. Uses of Large Structures

Porous absorbent polymer macrostructures can be used for many purposes in many applications. For example, the macrostructure may include a packing container; Drug delivery mechanisms; Trauma cleaning apparatus; Burn treatment apparatus processing apparatus; Ion exchange column materials; Constituents; Agricultural or horticultural materials, such as seed sheets or water-soluble materials; And industrial applications for sludge or oil dehydrating agents, anti dewing agents, desiccants and humidity control materials.

Porous absorbent polymer macrostructures of the invention are useful when bonded to a carrier. Carriers useful in the present invention include absorbent materials such as cellulose fibers. The carrier may also be any other carrier, such as known in the art, such as nonwoven webs, tissue webs, foams, polyacrylate fibers, hollow polymer webs, synthetic fibers, metal foils, elastomers, and the like. The macrostructures can bind directly or indirectly to the carrier and can bind to the carrier via known chemical or physical bonds, including puncture agents or chemicals that react to attach the macrostructure to the carrier.

Because of the unique absorbent properties of the porous, absorbent polymer macrostructures of the present invention, the macrostructures are particularly suitable for use as absorbent cores in absorbent articles, particularly disposable absorbent articles. As used herein, an "absorbent article" refers to a product that absorbs and contains body excrement, and more specifically, refers to a product located on or around the wearer's body to absorb and contain various excreta released from the body. Say. In addition, "disposable absorbent products" are intended to be disposed of after one use. (I.e., in general, the original absorbent product is not intended to be washed, otherwise restored or reused as an absorbent product, even if any material or all absorbent products are to be recycled, reused, or compounded). As a preferred embodiment of the disposable absorbent article, the diaper 20 is shown in FIG. In the text, "diaper" generally refers to garments worn by infants and incontinence patients, which are worn around the wearer's lower body. However, the present invention can also be used in other absorbent articles such as incontinence briefs, incontinence pads, exercise panties, diaper inserts, sanitary napkins, facial tissues, and paper towels.

5 shows an unshrinked state (ie, by elasticity) with a portion of the cut structure and a portion of the diaper 20 in contact with the wearer when viewed by the observer to more clearly show the structure of the diaper 20 of the present invention. Is a perspective view showing the diaper 20 of the present invention in a state where all shrinkage is removed. The diaper 20 includes a liquid permeable top sheet 38 in FIG. A liquid impermeable backsheet 40 associated with the topsheet 38; An absorbent core 42 located between the top sheet 38 and the back sheet 40; An elastic member 44; And tape tab fasteners 46. Although the top sheet 38, the back sheet 40, the absorbent core 42 and the elastic member 44 may be assembled into various well-known shapes, the preferred diaper shape is generally in 1975, which is incorporated herein by reference. US Patent No. 3,860,003 issued to Buell on January 14. In addition, preferred shapes for this disposable diaper are described in US Pat. No. 4,808,178, issued to Aziz et al. On February 28, 1989; United States Patent No. 4,695,278, issued to Lawson on September 22, 1987; And US Pat. No. 4,816,025 to Foreman on March 28, 1989.

5 shows a preferred embodiment of the diaper 20 in which the top sheet 38 and the back sheet 40 extend simultaneously and generally have dimensions of a length and width larger than the absorbent core 41. The upper sheet 38 is coupled with the back sheet 40 and overlaps on the back sheet 40, thereby forming the perimeter of the diaper 20. The perimeter defines the outer perimeter or edge of the diaper 20. The perimeter includes a longitudinal edge 30 and an end edge 32.

The top sheet 38 is suitable for the wearer's skin and gives a soft feel and is non-irritating. Moreover, the topsheet 38 is liquid permeable, through which the liquid easily penetrates through its thickness. Suitable topsheets 38 are from a wide variety of materials such as porous foams, networked foams, hollow plastic films, natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers). It may be prepared or from a blend of natural or synthetic fibers. Preferably, the topsheet 38 is made of hydrophobic material to separate the wearer's skin from the liquid in the absorbent core 42.

Particularly preferred topsheet 38 comprises staple length polypropylene fibers having a denier of about 1.5, such as Hercules Type 151 polypropylene from Hercules Incorporated, Walmington, Delaware. . "Staple-length fibers" as used herein refers to fibers having a length of at least about 15.9 mm (0.62 inches).

There are many manufacturing techniques for manufacturing the top sheet 38. For example, the topsheet 38 can be made by weaving, nonwoven, radial bonding, or carding techniques. Preferred topsheets are carded and thermally bonded by means well known to those skilled in the textile arts. Preferably, topsheet 38 has a weight of about 18 to about 25 g / m 2, a minimum dry tensile strength of at least about 400 g per cm in the machine direction, and a wet tensile strength of at least about 55 g per cm in the transverse direction of the machine. .

The backsheet 40 is impermeable to liquid and made from a thin plastic film, although other flexible liquid impermeable materials may be used. The backsheet 40 prevents the excretions absorbed and contained in the absorbent core 42 from wetting products in contact with the diaper 20, such as bedsheets and underwear. Preferably, the backsheet 40 is a polyethylene film having a thickness of about 0.012 mm (0.5 mil) to about 0.051 cm (2.0 mil), although other flexible liquid impermeable materials may be used. As used herein, "flexible" refers to a comfortable material that fits the universal shape and appearance of the wearer's body.

Suitable polyethylene films are commercially available under the trade name Film N. 8020 from Monsanto Chemical Corporation. The backsheet 40 is preferably embossed and / or matted to provide a more cloth-like appearance. Moreover, the backsheet 40 allows vapors to escape from the absorbent core 42 but blocks the excrement from passing through the backsheet 40.

The size of the backsheet 40 depends on the size of the absorbent core 42 and the exact diaper design chosen. In a preferred embodiment, the backsheet 40 has a modified hourglass shape extending beyond the absorbent core 42 by a minimum distance of at least about 1.3 cm to about 2.5 cm (about 0.5 to about 1.Oin) around the entire diaper circumference. Have

The top sheet 38 and the back sheet 40 are joined together in a suitable manner. The term "coupled" in the text refers to a shape in which the top sheet 38 is directly bonded to the back sheet 40 by fixing the top sheet 38 directly to the back sheet 40, and the top sheet 38 is fixed to the intermediate member. After that, the upper sheet 38 is indirectly bonded to the rear sheet 40 by fixing it to the rear sheet 40. In a preferred embodiment, the topsheet 38 and the backsheet 40 are secured directly to each other around the diaper by attachment means (not shown) or other attachment means, such as adhesive, as known in the art. For example, the topsheet 38 can be secured to the backsheet 40 using a constant continuous layer of adhesive, a patterned layer of adhesive, or an arrangement of individual lines or spots of the adhesive.

Tape tab fasteners 46 are typically applied to the rear waistband region 24 of the diaper 20 to provide a joining means for holding the diaper to the wearer. Tape tab fasteners 46 may be any of those well known in the art, such as the bonding tape described in US Pat. No. 3,848,594, issued to Buwell on November 19, 1974, which is incorporated herein by reference. Can be. Such tape tab fasteners 46 or other diaper fastening means are typically applied near the corners of the diaper 20.

The elastic members 44 are arranged close to the periphery of the diaper 20, preferably along the longitudinal edges 30, respectively, so that the elastic member 44 pulls the diaper 20 against the wearer's leg. It is supposed to be maintained. In addition, the elastic member 44 may be disposed adjacent one or both of the end edges 32 of the diaper 20 to provide a waistband as well as a cuff of the leg. For example, suitable waistbands are described in US Pat. No. 4,515,595, issued to Kievit et al. On May 7, 1985, which is incorporated herein by reference. In addition, methods and apparatus suitable for making disposable diapers having elastically shrinkable elastic members are described in US Pat. No. 4,081,301, issued to Buwell on March 28, 1978, which is incorporated herein by reference.

The elastic member 44 is fixed in the diaper 20 in a state that is elastically retractable to effectively shrink or gather the diaper 20 in an unbonded shape. The elastic member 44 may be fixed in an elastically retractable state in two or more ways. For example, the elastic member 44 may be stretched and fixed while the diaper 20 is in a non-constricted state. In addition, the diaper 20 may be shrunk by, for example, wrinkles, and the elastic member 44 is fixed and connected to the diaper 20 while it is present in a loose or unstretched state.

In the embodiment shown in FIG. 5, the elastic member 44 extends along a portion of the length of the diaper 20. In addition, the elastic member 44 extends the entire length of the diaper 20, or any other length suitable for providing an elastically shrinkable line. The length of the elastic member 44 depends on the diaper design.

The elastic member 44 may take a number of shapes. For example, the width of the elastic member 44 can vary from about 0.25 mm (0.01 in) to about 25 mm (1.0 in) or more; The elastic member 44 may comprise a single strand of elastic material, or may comprise several parallel or non-parallel elastic material strands; Alternatively, the elastic member 44 may be rectangular or curved. Moreover, the elastic member 44 may be secured to the diaper in some manner known in the art. For example, the elastic member 44 may be ultrasonically coupled or heated and pressurized in the diaper 20 using various bonding patterns, or the elastic member 44 may simply be glued to the diaper 20. Can be combined.

The absorbent core 42 of the diaper 20 is located between the top sheet 38 and the back sheet 40. Absorbent core 42 is made in a variety of sizes and shapes (eg, rectangular, hourglass, asymmetric, etc.) and can be made from a variety of materials. However, the total absorbent capacity of the absorbent core 42 should be compatible with the liquid fill design for the intended use of the absorbent article or diaper. Moreover, the size and absorbent capacity of the absorbent core 42 can be varied to accommodate the wearer from infant to adult. Absorbent core 42 comprises a porous, absorbent macrostructure of the present invention.

A preferred embodiment of the diaper 20 has a rectangular absorbent core 42. As shown in FIG. 9, the absorbent core 42 includes an absorbent member 48 comprising an envelope web 50 and a porous absorbent polymer macrostructure 52 disposed within the envelope web 50. It is preferable to include. The macrostructure 52 is encased in the envelope web 50 and minimizes the potential for precursor particles to migrate to the topsheet, providing an additional liquid transfer layer between the topsheet 38 and the macrostructure 52. Improve liquid containment and minimize rewet. As shown in FIG. 6, only one envelope web 50 is wrapped around the macrostructure 52 by pleats to form the first layer 54 and the second layer 56. The edge 58 of the envelope web 50 is sealed around it by any conventional means such as an adhesive 59 (shown), ultrasonic bonding, or heat / pressure bonding to form a bag. Envelope web 50 includes a number of materials, including nonwoven webs, paper webs, or webs of absorbent materials such as tissue paper. The envelope web 50 preferably comprises a nonwoven web similar to the web used to form the topsheet 38. The nonwoven web is preferably hydrophilic such that the liquid quickly passes through the envelope web 50. Similar laminated absorbent members (laminates) are described in more detail in US Pat. No. 4,578,068 to Kramer et al. On March 25, 1986, incorporated herein by reference.

In addition, the absorbent core 42 of the present invention consists only of one or more (multiple) porous absorbent polymer macrostructures of the present invention; Comprise a composite of layers comprising the macrostructure of the invention; Or any other absorbent core configuration includes one or more macrostructures of the present invention.

7 shows a sheet 62 of porous absorbent polymer macrostructure located below the absorbent member 60 (ie, between the absorbent member 60 and the backsheet 40) and the absorbent member 60 in the form of a modified water clock. An optional embodiment of a diaper 120 including a dual layer absorbent core 142 is shown.

The absorbent member 60 quickly collects and temporarily retains the discharged liquid, and sucks this liquid from the initial contact point and moves it to other portions of the absorbent member 60 and to the macrostructure sheet 62. Absorbent bonsai 60 preferably comprises a web or batt of the fiber material. Various types of fibrous materials may be used in the absorbent member 60, such as the fibrous materials already mentioned herein. Cellulose fibers are generally preferred for use herein, and wood pulp fibers are particularly preferred. Absorbent member 60 may also contain a specific amount of particulate absorbent polymer composition. Absorbent member 60 may contain, for example, up to about 50% by weight of the polymer composition. In the most preferred embodiment, the absorbent member 60 contains 0 to about 8 weight percent of the particulate absorbent polymer composition. In another preferred embodiment, the absorbent member 60 comprises chemically reinforced cellulose fibers already mentioned herein. Exemplary embodiments of absorbent members 60 useful in the present invention include US Pat. No. 4,673,402, issued to Weisman et al. On June 16, 1987; And US Pat. No. 4,834,735, issued May 30, 1989 to Alemany et al. These patents are incorporated herein by reference. Particularly preferred for use herein is an absorbing zone having a receiving zone and a storage zone having an average density lower than the storage zone and a lower average basis weight per unit area so that the receiving zone has an effective, efficient and rapid receipt of the discharged liquid.

Absorbing member 60 may be of any desired shape, for example rectangular, oval, rectangular, asymmetrical or water clocked. The shape of the absorbent member 60 may limit the general shape of the resulting diaper 120. In the preferred embodiment shown in FIG. 7, the absorbent member 60 is in the form of a water clock.

The macrostructure sheet 62 of the present invention need not have the same size as the absorbent member 60 and, in fact, has an upper surface that is nearly smaller or larger than the upper surface area of the absorbent member 60. As shown in FIG. 7, the macrostructure sheet 62 is smaller than the absorbent member 60 and has an upper surface area of about 0.10 to about 1.0 times that of the absorbent member 60. Most preferably, the upper surface area of the macrostructure sheet 62 has an upper surface area of about 0.10 to about 0.75, most preferably about 0.10 to about 0.5 times the absorbent member 60. In an optional embodiment, the absorbent member 60 is smaller than the macrostructure sheet 62 and has an upper surface area of about 0.25 to about 1.0 times, more preferably about 0.3 to about 0.95 times the macrostructure sheet 62. In an optional embodiment, the absorbent member 60 preferably includes chemically strengthened cellulose fibers.

The macrostructure sheet 62 is preferably placed in a specific positional relationship with respect to the backsheet 40 and / or absorbent member 60 of the diaper. More particularly, macrostructure sheet 62 is generally placed at the forefoot of the diaper so that it is most effectively placed to receive and retain the discharged liquid.

Alternatively, in a preferred embodiment, a plurality of macrostructures, preferably about 2 to about 6 macrostructure strips or sheets, may be used in place of the single macrostructure sheet 62 shown in FIG. In addition, additional absorbent layers, absorbent members or absorbent structures may be placed on the absorbent core 142. For example, an additional absorbent member is positioned between the macrostructure sheet 62 and the backsheet 40 such that liquid passes through the macrostructure sheet 62 to form another portion of the absorbent core 142 or the macrostructure sheet. It is also possible to provide a reserve for the absorbent core 142 and / or layers to be distributed to 62. The macrostructure sheet 62 may also be selectively positioned over the absorbent member 60 to be positioned between the topsheet 38 and the absorbent member 60.

FIG. 8 includes a rectangular absorbent member 260 and another double-worm absorbent core 242 comprising three elongated parallel structures spaced in parallel between the absorbent member 260 and the backsheet 40. Another embodiment of a diaper 220 is shown.

Absorbent member 260 quickly collects and temporarily retains secretion fluid, wicking the liquid and moves it from the initial point of contact of absorbent member 260 to another portion and to macrostructure strip 262. Such absorbent member 260 preferably comprises a web or batt of fibrous material, most preferably chemically reinforced cellulosic fibers as described above herein. The macrostructure strip 262 together serves to receive and retain secretion. By separating the macrostructure strip 262 from other strips, a more effective surface area is provided for receiving and retaining secretion. This is particularly possible because the spaced macrostructure strips 262 can swell and stretch in their width direction without disturbing the performance of adjacent strips.

In use, the diaper 20 is placed in the rear waistband region beneath the wearer's back and applied to the wearer by pulling the rest of the diaper 20 between the wearer's legs such that the front waistband region is positioned over the wearer's front. . The tape-tab fasteners 46 preferably protect the outer facing area of the diaper 20. In use, disposable diapers or other absorbent articles incorporating the porous absorbent macrostructures of the present invention tend to distribute and store liquids more quickly and efficiently, and tend to remain dry due to the high absorbent capacity of the macrostructures. Disposable diapers incorporating the macrostructures of the present invention may also be thinner and more flexible.

Synthetic urine

The particular synthetic urine used in the test method of the present invention is referred to herein as "Synthetic Urine." Synthetic urine is commonly known as Jayco SynUrine and is available from Jayco Pharmaceuticals Company, Camp Hill, PA. The composition of the synthetic urine is as follows: 2.0 g / L KCl; 2.0 g / l Na 2 SO 4; 0.85 g / l of (NH 4) H 2 PO 4; 0.15 g / l of (NH 4) 2 HPO 4; 0.19 g / l CaCl 2; And 0.23 g / l MgCl 2. All chemicals are for reagents. The pH of synthetic urine is in the range of 6.0 to 6.4.

Test Methods

A. Absorption Capacity of Precursor Particles

The polymer composition is placed in a “tea bag”, immersed in excess synthetic urine for a period of time and then centrifuged for a period of time. The ratio of initial weight minus initial weight to net weight of polymer composition after centrifugation to initial weight determines the absorbent capacity.

The following procedure is performed under standard laboratory conditions at 23 ° C. (73 ° F.) and 50% relative humidity. Using a 6 cm x 12 cm cutting die, the tea bag material is cut and folded in half vertically and sealed along two sides with a T-bar sealer to make a 6 cm x 6 cm square tea bag. The tea bag quality used was Mr. Dexter Corp., Windsor Locks, Connecticut, United States. H. Grade 1234 heat sealable material or equivalent available from C.H. Dexter. In some cases, a more porous tea bag material temperature should be used to retain the fine particles. 0.200 g ± 0.005 g of the polymer composition is weighed onto the weighing paper and transferred to the tea bag, and then the tea bag top (opening end) is sealed. The top of the empty tea bag is sealed and used as a blank. About 300 ml of synthetic urine is poured into a 1,000 ml beaker. Soak a blank tea bag in synthetic urine. The tea bag containing the polymer composition (sample tea bag) is held horizontally to evenly distribute the material throughout the tea bag. Place the tea bag on the surface of the synthetic urine. The tea bag is wet for less than 1 minute, then completely immersed and soaked for 60 minutes. After about two minutes of soaking the first sample, the second set of tea bags prepared in the same way as the first blank and sample tea bags are soaked in the same manner as the first set and then soaked for 60 minutes. After the above immersion time has elapsed, the tea bags are quickly removed from the synthetic urine for each tea bag sample set (with tongs). The sample is then centrifuged as described below. The centrifuge used was a Delux Dynac II Centrifuge, Fisher Model No. 05-100-26 or equivalent, available from Fisher Scientific Co., Pittsburgh, PA. The centrifuge shall be equipped with a direct reading tachometer and an electric brake. The centrifuge also has a circular hole of 8,435 inches (21.425 cm) in diameter, 7.935 inches (20.155 cm) in inner diameter, and about 106 3/32 inches (0.238 cm) in diameter, spaced equally around the circumference of the outer wall, respectively. Has nine rows with With a basket floor with six 1/4 inch (0.635 cm) diameter drain holes equally spaced about the circumference of the basket floor from the inner surface of the outer wall to the center of the drain hole A cylindrical insert basket or equivalent is mounted. The basket is mounted in the centrifuge to brake as well as rotate with the centrifuge. The sample teabag absorbs the initial force with the folded end of the teabag in the centrifuge rotational direction being placed in the centrifuge basket. The blank tea bag is placed on either side of the corresponding sample tea bag. The second set of sample tea bags is placed opposite the first set of blank tea bags to balance the centrifuge. The centrifuge is operated and quickly accelerated to a stable speed of 1500 rpm. Once the centrifuge has stabilized at 1500 rpm, set the timer to 3 minutes. After 3 minutes, turn off the centrifuge and apply the brake autonomous. The first sample tea bag and the first blank tea bag are removed and weighed separately. The procedure is repeated for the second sample tea bag and the second blank tea bag. The absorbent capacity (ac) for each sample is calculated as follows: ac = (sample teabag weight after centrifugation-blank teabag weight after centrifugation-dry polymer composition weight) / (dry polymer composition weight), used in the present invention Absorbent capacity values to be given are the average absorbent capacity of two samples.

B. Fluid Stability

It is an object of the present invention to determine the stability of aggregates upon exposure to synthetic urine. The macrostructure sample is placed in a shallow dish. Excess synthetic urine is added to the macrostructure. Observe the swelling of the macrostructure until equilibrium is reached. During the observation of the swelling of the macrostructure, small particles emerge from the main aggregate, platelet-like particles float from the main aggregate, or particles swell away from the main aggregate and float only in two dimensions in the XY plane. Observe that. If the aggregate has a large number of falling component particles, the macrostructure is considered to be unstable. Large structures should also be observed for isotropic swelling. The macrostructure is considered to be stable if the aggregate is relatively stable and the relative geometry and spacing relationship of precursor particles and pores is maintained after the test procedure. It is desirable that the fluid stable macrostructures can be obtained in a swollen state without falling off.

C. Precursor Particle Size and Mass Average Particle Size

Sieving the sample through a set of 19 sieves ranging in size from standard # 20 sieves (850μ) to standard # 400 sieves (38μ) based on the particle size distribution based on the weight percent of the 10 g bulk sample of the precursor particles. Decide by These sieves are standard sieves of Gilson Company, Inc., Washington, Ohio. The apparatus used cannot support all 19 sieves at one time, so the method is carried out at once with three stacks of sieves. One stack contains # 20, 25, 30, 35, 40, 45, and 50 sieves and a sieve pan, and the second stack contains # 60, 70, 80, 100. , 120 and 140 sieve and sieve pans, and the third stack contains # 170, 200, 230, 270, 325 and 400 sieve and sieve pans. At this time, each of the precursor particles remaining in these sieves is weighed to measure the particle size distribution based on the weight%.

The first stack of sieves is placed on a shaker and a sample of 10.0 g ± 0.00 g is placed on sieve # 20. The shaker used was Gilson Company, Washington, Ohio, Vibratory 3-in, Sieve Shaker Model SS-5 from Incorporated. The stack is shaken for 3 minutes at about 2100 vibrations per minute ("6" on the measuring dial). The sieve pan is then removed and the stack placed elsewhere for later weighing. Using a soft brush, correct the remaining sample on the sieve pan on weighed paper. A second stack of sieves is placed on a shaker and the weighed paper is transferred onto sieve # 60. The second stack is shaken for 3 minutes at about 2100 vibrations per minute, then the sample remaining on the sieve pan is transferred to a weighed paper and the stack is placed aside. A third stack of sieves is placed on a shaker and the sample on weighed paper is transferred to sieve # 170. The third stack is stirred for 3 minutes at about 2100 vibrations per minute. Using a soft brush, correct the contents of each given sieve onto a weighed piece of paper. The sample is weighed on a standard balance with 3 decimal places and the weight of the sample for the particular sieve is recorded. The above steps are repeated using freshly weighed paper for each sample, each sieve, and the third stack of sieves and then the sample remaining on the sieve pan. This method is repeated for two additional 10 g samples. The average weight of three samples of each sieve determines the average particle size distribution based on the weight percent for each sieve size.

The mass average particle size of the 10 g bulk sample is calculated by the following equation.

maps = ∑ (D _i x Mi) / ∑Mi

Where maps is the mass mean particle size: Mi is the weight of the particles on a particular sieve; Di is the "size variable" for the particular sieve. The sieve size variable Di is defined as the average of the size (μ) of the highest sieve nearby. For example, standard # 50 has a size variable 355μ which is equal to the size of the opening in standard # 45 (the highest size adjacent). The mass mean particle size for use herein is the average of the mass mean particle sizes of three samples.

Precursor Particle Examples

The jacketed 10 liter twin arm stainless steel kneader is sealed with a lid. The kneader has two sigma-shaped blades measuring an opening of 220 mm x 240 mm and a depth of 240 mm and rotating to a diameter of 120 mm. A monomer aqueous solution consisting of 37% by weight of monomer is prepared. The monomer consists of 75 mol% sodium acrylate and 25 mol% acrylic acid. 5500 g of aqueous monomer solution is supplied to the kneader vessel, and then purged with nitrogen gas to remove remaining trapped air. The two sigma-shaped blades are then rotated at a speed of 46 rpm and the jacket is heated by passing water at 35 ° C. through the jacket. 2.8 g sodium persulfate and 0.14 g L-ascorbic acid are added as polymerization initiators. After adding the initiator, polymerization is initiated for about 4 minutes. After 15 minutes of adding the initiator, the interior of the reaction system reaches a peak temperature of 82 ° C. The hydrated gel polymer is separated to a particle size of about 5 mm with continued stirring. The polymerization is initiated and the polymer material is removed from the kneader and after 60 minutes the lid is removed from the kneader.

The hydrated aqueous gel polymer thus obtained is sprayed on a standard # 50 size metal gauze and dried in hot air at 150 ° C. for 90 minutes. The dried particles are pulverized with a hammer mill and sieved with standard # 20 sieve (850μ) to obtain particles passing through standard # 20 sieve. The mass average particle size of these particles is 405 microns.

Specific embodiment of the method for manufacturing a macrostructure according to the present invention

Example 1

Precursor Particles 100 parts of precursor particles prepared according to the Example are placed in a 5 quart upright kitchen mixer. This precursor particle passes through a standard 50th sieve (300 microns) and has particles of a size remaining in the standard 100th sieve (150 microns). An aqueous treatment solution is prepared from 4.3 parts of Kemen plus (30% of the resin is active), 2.6 parts of water and 10.0 parts of methanol. This treatment solution is sprayed onto the precursor particles using a Preval nebulizer (available from The Precision Valve Corporation, Yonkers, NY). While operating the mixer at a slow speed, the treatment solution is sprayed onto the precursor particles for about 4 minutes until all of the solution is sprayed onto the particles. After spraying, the mixture of wet precursor particles is mixed at the highest fixed rate for 2 to 5 minutes. During this high speed mixing process, the methanol is evaporated to increase the tackiness of the treated mixture of precursor particles, thereby leaving them adhered to each other. The tacky mixture of treated precursor particles is then fed to an extrusion / compression unit. The extruder screw has a length of 8 inches (20.3 cm), has five flights, and each flight has a length of 1.5 inches (3.8 cm). The outer diameter of the extruder screw is 1.75 inches (4.45 cm), and the clearance between the screw and the housing is 0.20 inches (0.51 cm). The unit operates to rotate the extruder screw at 47 rpm. The mixture is extruded between two smooth post-treatment steel compression rolls (nip rolls) with a fixed (but adjustable) gap. The compression roll has a diameter of 8.975 inches (22.8 cm) and is operated at a speed of 5.4 rpm. The gap between the compression rolls is 0.015 inches (0.38 mm). The molded aggregate sheet is then separated to a length of approximately 12-15 inches (30-40 cm). The resulting aggregate sheet is heated in a forced air oven at 200 ° C. for 10 minutes to allow the chimen plus to react with the polymeric material on the surface of the precursor particles to form an effective food bond. The oven-cured sheet has a thickness (caliper) of about 0.031 inch (0.8 mm) and a width of about 1.95 inch (4.95 cm). A plasticizer solution containing 65 parts of glycerol and 35 parts of distilled water is sprayed onto the oven-cured sheet at a rate of 0.9 g of plasticizer solution per 1.0 g of the oven-cured sheet. About 1/2 hour after treatment with the plasticizer solution, the sheet has sufficient flexibility and tensile strength to be selected.

Example 2

In this embodiment, 100 parts of precursor particles prepared according to the precursor particle examples and having the particle size characteristics as described in Example 1 are used. An aqueous treatment solution prepared from a mixture of 6.0 parts of Kemen plus (30% active resin), 3.5 parts of water and 8.5 parts of glycerol is also used.

A reciprocating table or shuttle is used in conjunction with a pair of nebulizers to which the treatment solution is applied and a vibrating feeder to deposit precursor particles. Place the nebulizer and the feeder on the surface of the reciprocating table. As the surface of this table moves under the sprayer, the treatment solution is sprayed onto the table surface (or layer of particles) in a predetermined manner. As the table surface moves further down the feeder in the same direction, an amount of precursor particles are deposited over the table surface or the previous layer of treated particles. After the particles are deposited from the feeder to form their layer, the surface of the table is moved in the opposite direction to repeat the process of application / deposition of the treatment solution.

Initially, a predetermined amount of treatment solution is sprayed onto the moving table surface. After first spraying the table surface with the treatment solution, five layers of precursor particles (0.2 g / in ² particles per layer) are deposited from the feeder. After depositing each particle layer, a predetermined amount of treatment solution is sprayed on top of each layer. The amount sprayed onto the first layer of precursor particles as well as the amount of treatment solution initially sprayed onto the table surface is about 0.018 g / in ² . The amount of treatment solution sprayed onto the other four layers of precursor particles is about 0.036 g / in ² . As a result, each layer of precursor particles is treated with the same amount of treatment solution.

After lamination of the precursor particles and spraying of the treatment solution are completed, a relatively cohesive particle sheet is formed. The coherent sheet is then fed to the compression unit using a belt. The compression unit consists of two coated steel compression rolls with a fixed (but adjustable) gap. The compression roll has a diameter of about 8 inches (20 cm) and is operated at a speed of about 20 rpm. The gap between the compression rolls is 0.035 to 0.040 inch (0.9 to 1.0 mm). The resulting aggregate sheet (0.9-1.0 mm) is stored in a plastic bag at ambient room temperature (about 65-72 ° F., 18.3-22.2 ° C.) for about 24 hours. During this ambient curing process, Chimen Plus reacts with the polymeric material on the surface of the precursor particles to form an effective crosslink. The ambient temperature cured sheet has a thickness of about 0.050 to 0.060 inches (1.3 to 1.5 mm) and a width of about 4 inches (10 cm). Such ambient cured sheets have sufficient flexibility and tensile strength to handle without breaking or tearing.

Example 3

In this embodiment, the apparatus 301 shown in FIG. 9 is used. Precursor Particles Precursor particles prepared according to examples and having a size of 150 to 250 microns are used. An aqueous treatment solution is prepared from a mixture of 5.0 parts of Kemen plus (30% active resin), 7.1 parts of water and 12.7 parts of glycerol. The feeder 304 is a super feeder model # 210 SE-O0345 vibration feeder sold by Soliz Flow Control, North Carolina, USA. The nebulizer 304 is a nozzle assembly activated with a model 6218-1 / 4 JAU furious air, available from Spraying Systems Company, Wheaton, Illinois, USA. In the first two applications, nebulizers 304a and 304b deliver the treatment solution to the conveyor 303 at a rate of 39.8 g / minute. In subsequent applications, the nebulizers 304c-304f deliver the treatment solution to the conveyor 303 at a rate of 79.6 g / minute. Conveyor 303 is a mobile conveyor made of polyurethane and moves at a speed of 27 ft / min. The presser is a pair of compression rolls 306 having a diameter of 8 inches (20 cm) and a width of 12 inches (30.5 cm). The upper and lower rolls 306 are coated with # 934 plasma coatings available from Plasma Coatings, Inc., Connecticut, United States.

This example is carried out according to the following steps.

Step 1: Initially spray the treatment solution into the desired area of the conveyor in an amount of 0.025 g solution per square inch of conveyor.

Step 2: Substantially continuously deposit 0.2 g of precursor particles per square inch of conveyor in the same area as above.

Step 3: Spray the treatment solution to the first layer of precursor particles over a predetermined area of the conveyor in an amount of 0.025 g of treatment solution per square inch of conveyor.

Step 4: Laminating substantially continuously 0.2 g of precursor particles per square inch of conveyor in the same area as above.

Step 5: Spray the treatment solution to a second layer of precursor particles over a predetermined area of the conveyor in an amount of 0.050 g of treatment solution per square inch of conveyor.

Step 6: Repeat steps 3 and 4 three or more times in sequence (a) so that the entire initial spraying step and subsequent five lamination spraying steps are 0.25 g of treatment solution per square inch of conveyor, and (b) five lamination steps The total is to provide a total of 1 g of precursor particles per square inch of conveyor. At this point a web is formed.

Step 7: Pass the web through a compression roll. The gap between the compression rolls is 0.035 inch (0.9 mm). This produces a sheet with a density of 0.995 g / cc.

Step 8: The sheet is placed in a plastic bag and allowed to cure for 48 hours at ambient temperature (72 ° F., 22.2 ° C.).

The resulting sheet has good flexibility, gel blocking properties and wet bonding.

Claims (64)

(i) a plurality of precursor particles bonded to each other at a surface and comprising a substantially water-insoluble and absorbent hydrogel-forming polymeric material having anionic functionality; Porous including the aggregate (aggregate) bond between the particles comprising the epichlorohydrin addition product in an amount sufficient to cause effective surface cross-linking - and (ii) a cationic amino to react with polymer material at the surface of the precursor particles As an absorbent macrostructure, The intergranular aggregated body has pores between adjacent precursor particles, the pores are connected to each other by interconnection channels to form a liquid permeable macrostructure, with a circumscribed dry volume of greater than 0.008 kPa. Large porous absorption macrostructures. The method of claim 1, Large structure with a perimeter dry volume greater than 10㎣ . The method of claim 2, Large structure with a circumferential dry volume greater than 500 mm 3 and a density of 0.7 to 1.3 g / cc. The method of claim 3, wherein Macrostructure having a mass average particle diameter of the precursor particles of 20 to 600 microns . The method of claim 4, wherein A macrostructure having a mass average particle diameter of the precursor particles of 20 to 300 microns . The method of claim 5, A macrostructure , which is a sheet having a thickness of at least 0.2 mm and a density of 0.8 to 1.1 g / cc . The method of claim 6, Macrostructure further comprises 5 to 100 parts by weight of plasticizer per 100 parts by weight of precursor particles. The method of claim 7, wherein A macrostructure, wherein the plasticizer comprises a mixture of glycerol and water in a weight ratio of 0.5: 1 to 2: 1 . The method of claim 2, Macrostructures wherein the anionic functional group of the polymeric material is a carboxyl group. The method of claim 9, Starch-acrylonitrile graft copolymers in which the polymeric material is hydrolyzed; Partially neutralized starch-acrylonitrile graft copolymers; Starch-acrylic acid graft copolymers; Partially neutralized starch-acrylic acid graft copolymers; Saponified vinyl acetate-acrylic ester copolymers; Hydrolyzed acrylonitrile copolymers; Hydrolyzed acrylamide copolymers; Slightly reticulated crosslinked products of the aforementioned copolymers; Partially neutralized polyacrylic acid; Slightly reticulated crosslinked product of partially neutralized polyacrylic acid; And macrostructures selected from the group consisting of mixtures thereof. The method of claim 9, And the cationic amino-epichlorohydrin adduct is 0.1-5 parts by weight of cationic polymeric amino-epichlorohydrin resin per 100 parts by weight of precursor particles. The method of claim 11, Macrostructures wherein the cationic polymeric resin is the reaction product of epichlorohydrin and polyethyleneimine or polyamide-polyamine. The method of claim 12, A macrostructure wherein the cationic polymeric resin is the reaction product of epichlorohydrin with polyamide-polyamine derived from polyalkylene polyamine and C ₃ -C ₁₀ divalent carboxylic acid. The method of claim 13, A macrostructure wherein the polyamide-polyamine is derived from a polyethylene polyamine having 2 to 4 ethylene units and a C ₄ -C ₆ saturated aliphatic dicarboxylic acid, wherein the amount of cationic polymeric resin is 0.5 to 2.5 parts by weight per 100 parts by weight of precursor particles. The method of claim 14, Macrostructures in which polyamide-polyamines are derived from diethylenetriamine and adipic acid. Liquid permeable topsheets; A liquid impermeable backsheet associated with the topsheet; And an absorbent core comprising one or more macrostructures according to claim 1, located between these topsheets and backsheets. The method of claim 16, An absorbent article, wherein the absorbent core further comprises an absorbent member comprising chemically strengthened cellulosic fibers between the topsheet and the macrostructure. The method of claim 17, Absorbent product that is a diaper. (i) a plurality of precursor particles bonded to each other at a surface and comprising a substantially water-insoluble and absorbent hydrogel-forming polymer material having a carboxyl group and having a mass average particle diameter of 20 to 300 microns ; (ii) 0.1 to 5 parts by weight of cationic polymeric amino-epichlorohydrin resin per 100 parts by weight of the precursor particles, reacting with a polymeric material at the surface of the precursor particles to form an ester crosslink; (iii) a flexible porous absorbent sheet comprising an intergranular aggregated aggregate comprising 5 to 60 parts by weight of a plasticizer per 100 parts by weight of the precursor particles and having a thickness of at least 0.2 mm and a density of 0.8 to 1.1 g / cc, here, with pores between the precursor adjacent the coupling assembly between the particle, the pores are interconnecting channels are connected by forming the liquid-permeable sheet, a large flexible porous absorbent sheet than 500 sheets circumference drying volume ㎣. The method of claim 19, A sheet having a thickness of 0.5 mm to 10 mm . The method of claim 20, A sheet having a thickness of 1 mm to 3 mm and a density of 0.9 to 1.0 g / cc. The method of claim 20, Starch-acrylonitrile graft copolymers in which the polymeric material is hydrolyzed; Partially neutralized starch-acrylonitrile graft copolymers; Starch-acrylic acid graft copolymers; Partially neutralized starch-acrylic acid graft copolymers; Saponified vinyl acetate-acrylic ester copolymers; Hydrolyzed acrylonitrile copolymers; Hydrolyzed acrylamide copolymers; Slightly reticulated crosslinked products of the aforementioned copolymers; Partially neutralized polyacrylic acid; Slightly reticulated crosslinked product of partially neutralized polyacrylic acid; And a sheet consisting of a mixture thereof. The method of claim 22, A sheet having a particle size of at least 95% by weight of the precursor particles of 150 microns to 300 microns . The method of claim 22, The sheet wherein the cationic polymeric resin is the reaction product of epichlorohydrin and polyethyleneimine or polyamide-polyamine. The method of claim 24, The sheet wherein the cationic polymeric resin is a reaction product of epichlorohydrin with polyamide-polyamine derived from polyalkylene polyamine and C ₃ -C ₁₀ divalent carboxylic acid. The method of claim 25, A sheet wherein the polyamide-polyamine is derived from polyethylene polyamine having 2 to 4 ethylene units and C ₄ -C ₆ saturated aliphatic dicarboxylic acid, wherein the amount of cationic polymeric resin is 0.5 to 2.5 parts by weight per 100 parts by weight of precursor particles. The method of claim 26, A sheet wherein polyamide-polyamine is derived from diethylenetriamine and adipic acid. The method of claim 26, A sheet wherein the plasticizer comprises a mixture of glycerol and water in a weight ratio of 0.5: 1 to 2: 1 . The method of claim 28, A sheet wherein the amount of plasticizer is 10 to 30 parts by weight per 100 parts by weight of precursor particles. Liquid permeable topsheets; A liquid impermeable backsheet associated with the topsheet; And disposed between these topsheet and the backsheet, the absorbent article comprising an absorbent core comprising at least one absorbent structure according to claim 19. The method of claim 30, An absorbent article, wherein the absorbent core further comprises an absorbent member comprising chemically strengthened cellulosic fibers between the topsheet and the absorbent structure. The method of claim 31, wherein An absorbent article, wherein the absorbent structure comprises two to six elongated strips spaced in parallel. The method of claim 32, Absorbent product that is a diaper. (a) providing a plurality of precursor particles of hydrogel-forming polymeric material having anionic functionality and are substantially water-insoluble and absorbent; (b) treating the precursor particles with an amount of cationic amino-epichlorohydrin adduct sufficient to react with the polymeric material at the surface of the precursor particles to effect effective surface crosslinking; (c) physically bonding the treated precursor particles to form an aggregate having pores connected to each other by interconnect channels; And (d) reacting the cationic adduct with the polymeric material of the precursor particles, resulting in effective surface crosslinking and providing a porous and absorbent intergranular aggregated macrostructure. The method of the porous structure to absorb large liquid-permeable by, comprising a coupling assembly between the particles having pores connected to each other by the interconnect channels including a. The method of claim 34, wherein and (d) shaping the aggregate before step . 36. The method of claim 35 wherein A method of forming an aggregate into sheets having a thickness of at least 0.2 mm and a density of 0.8 to 1.1 g / cc . The method of claim 34, wherein The mass mean particle size of the precursor particles is 20 to 600 microns . The method of claim 37, The mass mean particle size of the precursor particles is 20 to 300 microns . The method of claim 37, Starch-acrylonitrile graft copolymers in which the polymeric material is hydrolyzed; Partially neutralized starch-acrylonitrile graft copolymers; Starch-acrylic acid graft copolymers; Partially neutralized starch-acrylic acid graft copolymers, saponified vinyl acetate-acrylic ester copolymers; Hydrolyzed acrylonitrile copolymers; Hydrolyzed acrylamide copolymers; Slightly reticulated crosslinked products of the aforementioned copolymers; Partially neutralized polyacrylic acid; Slightly reticulated crosslinked product of partially neutralized polyacrylic acid; And mixtures thereof. The method of claim 34, Comprising the step of processing the precursor particles, the precursor particles per 100 parts by weight of 5 to 100 parts by weight of plasticizer added. The method of claim 40, Wherein the plasticizer comprises a mixture of glycerol and water in a weight ratio of 0.5: 1 to 2: 1 . The method of claim 40, (d) performing the step at 18 ° C. to 35 ° C. for 12 to 48 hours . The method of claim 42, (d) performing the step at 18 ° C-25 ° C for 24 to 48 hours . The method of claim 34, (d) performing the step at 50 ° C to 205 ° C for 1 to 20 minutes . The method of claim 44, (d) performing the step 5 to 15 minutes at 180 ℃ to 200 ℃ . The method of claim 44, (d) comprises a massive structure after the step, the further step of processing a huge structure of 100 parts by weight of 5 to 100 parts by weight of a plasticizer. 47. The method of claim 46 wherein Wherein the plasticizer comprises a mixture of glycerol and water in a weight ratio of 0.5: 1 to 2: 1 . The method of claim 34, wherein The cationic amino-epichlorohydrin adduct is a cationic polymeric amino-epichlorohydrin resin and is applied in step (b) in an amount of 0.1 to 5 parts by weight per 100 parts by weight of precursor particles. The method of claim 48, The cationic polymeric resin is the reaction product of epichlorohydrin and polyethyleneimine or polyamide-polyamine. The method of claim 49, And the cationic polymeric resin is the reaction product of epichlorohydrin with polyamide-polyamine derived from polyalkylene polyamine and C ₃ -C ₁₀ divalent carboxylic acid. 51. The method of claim 50, Wherein the polyamide-polyamine is derived from polyethylene polyamine having 2 to 4 ethylene units and C ₄ -C ₆ saturated aliphatic dicarboxylic acid, and the cationic polymeric resin is applied at 0.5 to 2.5 parts by weight per 100 parts by weight of precursor particles. The method of claim 51, Wherein the polyamide-polyamine is derived from diethylenetriamine and adipic acid. (a) hydrolyzed starch-acrylonitrile graft copolymers; Partially neutralized starch-acrylonitrile graft copolymers: starch-acrylic acid graft copolymers, partially neutralized starch-acrylic acid graft copolymers; Saponified vinyl acetate-acrylic ester copolymers; Hydrolyzed acrylonitrile copolymers, hydrolyzed acrylamide copolymers; Slightly reticulated crosslinked products of the aforementioned copolymers; Partially neutralized polyacrylic acid; Slightly reticulated crosslinked product of partially neutralized polyacrylic acid; And practically selected from the group consisting of mixtures thereof, and water-insoluble absorbent hydrogel-forming polymer phase containing the substance, and providing a plurality of the precursor particles having the mass average particle size of 20 to 300 microns. (b) a pH of 4 to 9 and (i) 0.1 to 5 parts by weight of cationic polymeric amino-epichlorohydrin resin per 100 parts by weight of precursor particles; And optionally (ii) applying an aqueous treatment solution comprising 5 to 60 parts by weight of a plasticizer per 100 parts by weight of precursor particles to the precursor particles ; (c) physically bonding the treated precursor particles to form an aggregate having pores connected to each other by interconnect channels; (d) forming the aggregate into sheets; And (e) reacting the cationic polymeric resin with the polymeric material of the precursor particles to effect effective surface crosslinking and to form a porous and absorbent interparticle bonded aggregate sheet (the thickness of the sheet is from 0.5 mm to 10 mm, the density being 0.8 to 1.1 g / cc and a dry volume of at least 500 mm ³ ) A method of making a porous, absorbent sheet of liquid permeability comprising an aggregated particle having pores connected to each other by interconnection channels, the method comprising: The method of claim 53, A method of providing a porous absorbent aggregate sheet having a thickness of 1 mm to 3 mm and a density of 0.9 to 1.0 g / cc . The method of claim 53, The particle size of at least 95% by weight of the precursor particles is 150 to 300 microns . The method of claim 55, (d) performing the step at 18 ° C. to 35 ° C. for 12 to 48 hours . The method of claim 56, wherein (d) performing the step at 18 ° C-25 ° C for 24 to 48 hours . The method of claim 55, step (d) is carried out at 50 ° C. to 205 ° C. for 1 to 20 minutes , (d) applying 5 to 60 parts by weight of plasticizer per 100 parts by weight of the aggregate sheet after step . The method of claim 58, Wherein the plasticizer comprises a mixture of glycerol and water in a weight ratio of 0.5: 1 to 2: 1 . The method of claim 59, (d) performing the step at 180 ° C. to 200 ° C. for 5 to 15 minutes . The method of claim 55, The cationic polymeric resin is the reaction product of epichlorohydrin and polyethyleneimine or polyamide-polyamine. 62. The method of claim 61, And the cationic polymeric resin is the reaction product of epichlorohydrin with polyamide-polyamine derived from polyalkylene polyamine and C ₃ -C ₁₀ divalent carboxylic acid. The method of claim 62, Wherein the polyamide-polyamine is derived from polyethylene polyamine having 2 to 4 ethylene units and C ₄ -C ₆ saturated aliphatic dicarboxylic acid, and the cationic polymeric resin is applied at 0.5 to 2.5 parts by weight per 100 parts by weight of precursor particles. The method of claim 63, wherein Wherein the polyamide-polyamine is derived from diethylenetriamine and adipic acid.